Concept-wise Practice

class11 MCQ Questions for Class 11

class11 se related questions ko ek jagah revise karein. Har question me bilingual content, answer feedback aur explanation available hai.

Practice Questions

1581 questions tagged with class11.

(12) गणित और (9) भौतिकी पुस्तकों में से (7) पुस्तकें चुननी हैं जिनमें कम से कम (4) गणित पुस्तकें हों। कितने तरीके हैं?

From (12) mathematics and (9) physics books (7) books are to be selected with at least (4) mathematics books. How many ways are there?

Explanation opens after your attempt
Correct Answer

C. (79200)

Step 1

Concept

The cases are (4), (5), (6), and (7) mathematics books. The correct sum is (79200).

Step 2

Why this answer is correct

The correct answer is C. (79200). The cases are (4), (5), (6), and (7) mathematics books. The correct sum is (79200).

Step 3

Exam Tip

मामले (4), (5), (6) और (7) गणित पुस्तकों के हैं। सही योग (79200) है।

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(13) व्यक्तियों में से (6) व्यक्तियों की समिति बनानी है और (2) विशेष व्यक्ति साथ में नहीं चुने जा सकते। कितने तरीके होंगे?

A committee of (6) persons is to be formed from (13) persons and (2) special persons cannot be selected together. How many ways are possible?

Explanation opens after your attempt
Correct Answer

A. (1386)

Step 1

Concept

Total ways are \(\binom{13}{6}=1716\) and ways with both special persons are \(\binom{11}{4}=330\). Hence (1716-330=1386).

Step 2

Why this answer is correct

The correct answer is A. (1386). Total ways are \(\binom{13}{6}=1716\) and ways with both special persons are \(\binom{11}{4}=330\). Hence (1716-330=1386).

Step 3

Exam Tip

कुल \(\binom{13}{6}=1716\) हैं और दोनों विशेष साथ हों तो \(\binom{11}{4}=330\) हैं। इसलिए (1716-330=1386) तरीके हैं।

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एक लीग में (18) टीमें हैं और हर दो टीमों के बीच (4) मैच खेले जाते हैं। कुल मैच कितने होंगे?

A league has (18) teams and (4) matches are played between every pair of teams. How many matches will be played?

Explanation opens after your attempt
Correct Answer

D. (612)

Step 1

Concept

The pairs of teams are \(\binom{18}{2}=153\). With (4) matches for each pair the total is (612).

Step 2

Why this answer is correct

The correct answer is D. (612). The pairs of teams are \(\binom{18}{2}=153\). With (4) matches for each pair the total is (612).

Step 3

Exam Tip

टीमों की जोड़ियां \(\binom{18}{2}=153\) हैं। हर जोड़ी के (4) मैच होने से कुल (612) मैच होंगे।

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(19) बिंदुओं में से (8) बिंदु एक सीध में हैं और (6) अन्य बिंदु अलग सीध में हैं। कोई अन्य (3) बिंदु एक सीध में नहीं हैं। कितने त्रिभुज बनेंगे?

Among (19) points (8) points are collinear and another (6) points are collinear on a different line. No other (3) points are collinear. How many triangles can be formed?

Explanation opens after your attempt
Correct Answer

C. (893)

Step 1

Concept

Total triples are \(\binom{19}{3}=969\). Failed triples are \(\binom{8}{3}+\binom{6}{3}=76\), so (969-76=893).

Step 2

Why this answer is correct

The correct answer is C. (893). Total triples are \(\binom{19}{3}=969\). Failed triples are \(\binom{8}{3}+\binom{6}{3}=76\), so (969-76=893).

Step 3

Exam Tip

कुल \(\binom{19}{3}=969\) त्रिक हैं। असफल त्रिक \(\binom{8}{3}+\binom{6}{3}=76\) हैं इसलिए (969-76=893) है।

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(22) बिंदुओं में से (9) बिंदु एक ही रेखा पर हैं और (6) अन्य बिंदु दूसरी रेखा पर हैं। कोई अन्य (3) बिंदु समरेखीय नहीं हैं। कितनी रेखाएं बनेंगी?

Among (22) points (9) points are collinear and another (6) points are collinear on a different line. No other (3) points are collinear. How many lines can be formed?

Explanation opens after your attempt
Correct Answer

B. (182)

Step 1

Concept

Total pairs are \(\binom{22}{2}=231\). Replacing \(\binom{9}{2}\) and \(\binom{6}{2}\) by (1), (1) for collinear groups gives (182).

Step 2

Why this answer is correct

The correct answer is B. (182). Total pairs are \(\binom{22}{2}=231\). Replacing \(\binom{9}{2}\) and \(\binom{6}{2}\) by (1), (1) for collinear groups gives (182).

Step 3

Exam Tip

कुल \(\binom{22}{2}=231\) जोड़ियां हैं। समरेखीय समूहों में \(\binom{9}{2}\) और \(\binom{6}{2}\) की जगह (1), (1) रेखा लेने से (182) मिलता है।

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(15) खिलाड़ियों में से (7) खिलाड़ी चुनने हैं और (6) विशेष खिलाड़ियों में से ठीक (3) खिलाड़ी चुने जाएं। कितने तरीके हैं?

From (15) players (7) players are to be selected and exactly (3) of (6) special players are selected. How many ways are there?

Explanation opens after your attempt
Correct Answer

D. (2520)

Step 1

Concept

Choose (3) from (6) special players and (4) from the remaining (9). The ways are \(\binom{6}{3}\binom{9}{4}=2520\).

Step 2

Why this answer is correct

The correct answer is D. (2520). Choose (3) from (6) special players and (4) from the remaining (9). The ways are \(\binom{6}{3}\binom{9}{4}=2520\).

Step 3

Exam Tip

(6) विशेष में से (3) और बाकी (9) में से (4) चुनेंगे। तरीके \(\binom{6}{3}\binom{9}{4}=2520\) हैं।

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(15) पुस्तकों में से (6) पुस्तकें चुननी हैं जिनमें दो विशेष पुस्तकें दोनों साथ न आएं। कितने तरीके हैं?

From (15) books (6) books are to be selected so that two special books do not appear together. How many ways are there?

Explanation opens after your attempt
Correct Answer

A. (4290)

Step 1

Concept

Total ways are \(\binom{15}{6}=5005\) and ways with both special books are \(\binom{13}{4}=715\). Hence (5005-715=4290).

Step 2

Why this answer is correct

The correct answer is A. (4290). Total ways are \(\binom{15}{6}=5005\) and ways with both special books are \(\binom{13}{4}=715\). Hence (5005-715=4290).

Step 3

Exam Tip

कुल \(\binom{15}{6}=5005\) हैं और दोनों विशेष साथ हों तो \(\binom{13}{4}=715\) हैं। इसलिए (5005-715=4290) तरीके हैं।

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(13) प्रश्नों में से (8) प्रश्न हल करने हैं और पहले (5) प्रश्नों में से कम से कम (3) प्रश्न अवश्य हल करने हैं। कितने चयन होंगे?

From (13) questions (8) are to be solved and at least (3) of the first (5) questions must be solved. How many selections are possible?

Explanation opens after your attempt
Correct Answer

C. (966)

Step 1

Concept

You can choose (3), (4), or (5) from the first (5) questions. The total is \(\binom{5}{3}\binom{8}{5}+\binom{5}{4}\binom{8}{4}+\binom{5}{5}\binom{8}{3}=966\).

Step 2

Why this answer is correct

The correct answer is C. (966). You can choose (3), (4), or (5) from the first (5) questions. The total is \(\binom{5}{3}\binom{8}{5}+\binom{5}{4}\binom{8}{4}+\binom{5}{5}\binom{8}{3}=966\).

Step 3

Exam Tip

पहले (5) में से (3), (4) या (5) प्रश्न चुने जा सकते हैं। कुल \(\binom{5}{3}\binom{8}{5}+\binom{5}{4}\binom{8}{4}+\binom{5}{5}\binom{8}{3}=966\) है।

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(9) लाल और (8) नीली गेंदों में से (6) गेंदें चुननी हैं जिनमें ठीक (3) लाल गेंदें हों। कितने तरीके हैं?

From (9) red and (8) blue balls (6) balls are to be selected with exactly (3) red balls. How many ways are there?

Explanation opens after your attempt
Correct Answer

B. (4704)

Step 1

Concept

Exactly (3) red and (3) blue balls are needed. The ways are \(\binom{9}{3}\binom{8}{3}=4704\).

Step 2

Why this answer is correct

The correct answer is B. (4704). Exactly (3) red and (3) blue balls are needed. The ways are \(\binom{9}{3}\binom{8}{3}=4704\).

Step 3

Exam Tip

ठीक (3) लाल और (3) नीली गेंदें चाहिए। तरीके \(\binom{9}{3}\binom{8}{3}=4704\) हैं।

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(9) पुरुषों और (8) महिलाओं में से (6) व्यक्ति चुनने हैं जिनमें कम से कम (3) महिलाएं हों। कितने तरीके हैं?

From (9) men and (8) women (6) persons are to be selected with at least (3) women. How many ways are there?

Explanation opens after your attempt
Correct Answer

D. (7756)

Step 1

Concept

The number of women can be (3), (4), (5), or (6). The correct sum is \(\binom{8}{3}\binom{9}{3}+\binom{8}{4}\binom{9}{2}+\binom{8}{5}\binom{9}{1}+\binom{8}{6}=7756\).

Step 2

Why this answer is correct

The correct answer is D. (7756). The number of women can be (3), (4), (5), or (6). The correct sum is \(\binom{8}{3}\binom{9}{3}+\binom{8}{4}\binom{9}{2}+\binom{8}{5}\binom{9}{1}+\binom{8}{6}=7756\).

Step 3

Exam Tip

महिलाएं (3), (4), (5) या (6) हो सकती हैं। सही योग \(\binom{8}{3}\binom{9}{3}+\binom{8}{4}\binom{9}{2}+\binom{8}{5}\binom{9}{1}+\binom{8}{6}=7756\) है।

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(10) लड़कों और (8) लड़कियों में से (7) विद्यार्थियों को चुनना है जिनमें ठीक (4) लड़कियां हों। कितने तरीके हैं?

From (10) boys and (8) girls (7) students are to be selected with exactly (4) girls. How many ways are there?

Explanation opens after your attempt
Correct Answer

C. (8400)

Step 1

Concept

Exactly (4) girls and (3) boys are needed. The ways are \(\binom{8}{4}\binom{10}{3}=8400\).

Step 2

Why this answer is correct

The correct answer is C. (8400). Exactly (4) girls and (3) boys are needed. The ways are \(\binom{8}{4}\binom{10}{3}=8400\).

Step 3

Exam Tip

ठीक (4) लड़कियां और (3) लड़के चाहिए। तरीके \(\binom{8}{4}\binom{10}{3}=8400\) हैं।

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(18) विद्यार्थियों में से (7) विद्यार्थियों की टीम बनानी है जिसमें (4) विशेष विद्यार्थी शामिल न हों। कितने तरीके हैं?

A team of (7) students is to be formed from (18) students excluding (4) special students. How many ways are there?

Explanation opens after your attempt
Correct Answer

B. (3432)

Step 1

Concept

After excluding (4) special students (14) students remain. So the number of ways is \(\binom{14}{7}=3432\).

Step 2

Why this answer is correct

The correct answer is B. (3432). After excluding (4) special students (14) students remain. So the number of ways is \(\binom{14}{7}=3432\).

Step 3

Exam Tip

(4) विशेष विद्यार्थियों को हटाने पर (14) विद्यार्थी बचते हैं। इसलिए \(\binom{14}{7}=3432\) तरीके होंगे।

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(16) सदस्यों में से (7) सदस्यों की समिति बनानी है जिसमें (3) निश्चित सदस्य अवश्य शामिल हों। कितने तरीके होंगे?

A committee of (7) members is to be formed from (16) members with (3) fixed members included. How many ways are possible?

Explanation opens after your attempt
Correct Answer

A. (715)

Step 1

Concept

The (3) members are fixed so the remaining (4) are chosen from (13). Hence \(\binom{13}{4}=715\).

Step 2

Why this answer is correct

The correct answer is A. (715). The (3) members are fixed so the remaining (4) are chosen from (13). Hence \(\binom{13}{4}=715\).

Step 3

Exam Tip

(3) सदस्य तय हैं इसलिए बाकी (4) सदस्य (13) में से चुने जाएंगे। अतः \(\binom{13}{4}=715\) होगा।

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(10) लड़कों और (9) लड़कियों में से (6) विद्यार्थियों का समूह बनाना है जिसमें कम से कम (2) लड़के और कम से कम (2) लड़कियां हों। कितने तरीके हैं?

From (10) boys and (9) girls a group of (6) students is to be formed with at least (2) boys and at least (2) girls. How many ways are there?

Explanation opens after your attempt
Correct Answer

C. (23310)

Step 1

Concept

The number of boys can be (2), (3), or (4). The total is \(\binom{10}{2}\binom{9}{4}+\binom{10}{3}\binom{9}{3}+\binom{10}{4}\binom{9}{2}=23310\).

Step 2

Why this answer is correct

The correct answer is C. (23310). The number of boys can be (2), (3), or (4). The total is \(\binom{10}{2}\binom{9}{4}+\binom{10}{3}\binom{9}{3}+\binom{10}{4}\binom{9}{2}=23310\).

Step 3

Exam Tip

लड़कों की संख्या (2), (3) या (4) हो सकती है। कुल \(\binom{10}{2}\binom{9}{4}+\binom{10}{3}\binom{9}{3}+\binom{10}{4}\binom{9}{2}=23310\) है।

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(18) वस्तुओं में से (7) वस्तुएं चुननी हैं और (6) विशेष वस्तुओं में से अधिकतम (2) चुनी जाएं। कितने तरीके हैं?

From (18) objects (7) objects are to be selected and at most (2) of (6) special objects are chosen. How many ways are there?

Explanation opens after your attempt
Correct Answer

C. (18216)

Step 1

Concept

The number of special objects can be (0), (1), or (2). The total is \(\binom{6}{0}\binom{12}{7}+\binom{6}{1}\binom{12}{6}+\binom{6}{2}\binom{12}{5}=18216\).

Step 2

Why this answer is correct

The correct answer is C. (18216). The number of special objects can be (0), (1), or (2). The total is \(\binom{6}{0}\binom{12}{7}+\binom{6}{1}\binom{12}{6}+\binom{6}{2}\binom{12}{5}=18216\).

Step 3

Exam Tip

विशेष वस्तुएं (0), (1) या (2) चुनी जा सकती हैं। कुल \(\binom{6}{0}\binom{12}{7}+\binom{6}{1}\binom{12}{6}+\binom{6}{2}\binom{12}{5}=18216\) है।

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(13) खिलाड़ियों में से (6) खिलाड़ियों का चयन करना है। एक कप्तान पहले से तय है और उसे चुना नहीं जाना है लेकिन उपकप्तान अवश्य चुना जाना है। कितने तरीके हैं?

From (13) players (6) players are to be selected. One captain is already fixed and must not be selected but the vice-captain must be selected. How many ways are there?

Explanation opens after your attempt
Correct Answer

B. (462)

Step 1

Concept

The captain is excluded and the vice-captain is fixed. The remaining (5) players are chosen from (11), so \(\binom{11}{5}=462\).

Step 2

Why this answer is correct

The correct answer is B. (462). The captain is excluded and the vice-captain is fixed. The remaining (5) players are chosen from (11), so \(\binom{11}{5}=462\).

Step 3

Exam Tip

कप्तान हट गया और उपकप्तान तय है। बाकी (5) खिलाड़ी (11) में से चुने जाएंगे इसलिए \(\binom{11}{5}=462\) है।

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(13) अलग-अलग खिलौनों में से विषम संख्या में खिलौने चुनने के कितने तरीके हैं?

In how many ways can an odd number of toys be selected from (13) different toys?

Explanation opens after your attempt
Correct Answer

C. (4096)

Step 1

Concept

The number of odd selections is \(2^{13-1}=4096\). Remember that even and odd selections are equal in such questions.

Step 2

Why this answer is correct

The correct answer is C. (4096). The number of odd selections is \(2^{13-1}=4096\). Remember that even and odd selections are equal in such questions.

Step 3

Exam Tip

विषम चयन की संख्या \(2^{13-1}=4096\) होती है। परीक्षा में सम और विषम चयन बराबर याद रखें।

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(14) अलग-अलग सिक्कों में से सम संख्या में सिक्के चुनने के कितने तरीके हैं?

In how many ways can an even number of coins be selected from (14) different coins?

Explanation opens after your attempt
Correct Answer

B. (8192)

Step 1

Concept

The number of even selections is \(2^{14-1}=8192\). Even and odd selections are equal.

Step 2

Why this answer is correct

The correct answer is B. (8192). The number of even selections is \(2^{14-1}=8192\). Even and odd selections are equal.

Step 3

Exam Tip

सम चयन की संख्या \(2^{14-1}=8192\) होती है। सम और विषम चयन बराबर होते हैं।

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(14) अलग-अलग कार्डों में से (6) कार्ड चुनने हैं जिनमें दो निश्चित कार्डों में से ठीक एक कार्ड हो। कितने तरीके हैं?

From (14) distinct cards (6) cards are to be selected containing exactly one of two fixed cards. How many ways are there?

Explanation opens after your attempt
Correct Answer

C. (1584)

Step 1

Concept

Choose (1) of the two fixed cards and (5) cards from the remaining (12). The ways are \(\binom{2}{1}\binom{12}{5}=1584\).

Step 2

Why this answer is correct

The correct answer is C. (1584). Choose (1) of the two fixed cards and (5) cards from the remaining (12). The ways are \(\binom{2}{1}\binom{12}{5}=1584\).

Step 3

Exam Tip

दो निश्चित कार्डों में से (1) चुनें और बाकी (5) कार्ड (12) में से चुनें। तरीके \(\binom{2}{1}\binom{12}{5}=1584\) हैं।

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(9) वरिष्ठ और (11) कनिष्ठ कर्मचारियों में से (7) लोगों की समिति बनानी है जिसमें वरिष्ठों की संख्या कनिष्ठों से कम हो। कितने तरीके हैं?

From (9) senior and (11) junior employees a committee of (7) is to be formed with fewer seniors than juniors. How many ways are there?

Explanation opens after your attempt
Correct Answer

B. (48840)

Step 1

Concept

The number of seniors can be (0), (1), (2), or (3). The total is \(\binom{9}{0}\binom{11}{7}+\binom{9}{1}\binom{11}{6}+\binom{9}{2}\binom{11}{5}+\binom{9}{3}\binom{11}{4}=48840\).

Step 2

Why this answer is correct

The correct answer is B. (48840). The number of seniors can be (0), (1), (2), or (3). The total is \(\binom{9}{0}\binom{11}{7}+\binom{9}{1}\binom{11}{6}+\binom{9}{2}\binom{11}{5}+\binom{9}{3}\binom{11}{4}=48840\).

Step 3

Exam Tip

वरिष्ठों की संख्या (0), (1), (2) या (3) हो सकती है। कुल \(\binom{9}{0}\binom{11}{7}+\binom{9}{1}\binom{11}{6}+\binom{9}{2}\binom{11}{5}+\binom{9}{3}\binom{11}{4}=48840\) है।

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(14) प्रश्नों में से (8) प्रश्न चुनने हैं और अंतिम (6) प्रश्नों में से कम से कम (4) प्रश्न चुनने हैं। कितने चयन होंगे?

From (14) questions (8) are to be selected and at least (4) of the last (6) questions must be selected. How many selections are there?

Explanation opens after your attempt
Correct Answer

B. (1414)

Step 1

Concept

You can choose (4), (5), or (6) from the last (6) questions. The total is \(\binom{6}{4}\binom{8}{4}+\binom{6}{5}\binom{8}{3}+\binom{6}{6}\binom{8}{2}=1414\).

Step 2

Why this answer is correct

The correct answer is B. (1414). You can choose (4), (5), or (6) from the last (6) questions. The total is \(\binom{6}{4}\binom{8}{4}+\binom{6}{5}\binom{8}{3}+\binom{6}{6}\binom{8}{2}=1414\).

Step 3

Exam Tip

अंतिम (6) में से (4), (5) या (6) प्रश्न चुने जा सकते हैं। कुल \(\binom{6}{4}\binom{8}{4}+\binom{6}{5}\binom{8}{3}+\binom{6}{6}\binom{8}{2}=1414\) है।

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(13) विद्यार्थियों में से (6) की टीम बनानी है जिसमें (2) विशेष विद्यार्थी दोनों शामिल हों या दोनों बाहर हों। कितने तरीके हैं?

From (13) students a team of (6) is to be formed in which (2) special students are either both included or both excluded. How many ways are there?

Explanation opens after your attempt
Correct Answer

B. (792)

Step 1

Concept

If both are included there are \(\binom{11}{4}=330\) ways and if both are excluded there are \(\binom{11}{6}=462\) ways. The total is (792).

Step 2

Why this answer is correct

The correct answer is B. (792). If both are included there are \(\binom{11}{4}=330\) ways and if both are excluded there are \(\binom{11}{6}=462\) ways. The total is (792).

Step 3

Exam Tip

दोनों शामिल हों तो \(\binom{11}{4}=330\) और दोनों बाहर हों तो \(\binom{11}{6}=462\) तरीके हैं। कुल (792) है।

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(14) कुर्सियों में से (7) कुर्सियां चुननी हैं और (5) खराब कुर्सियों में से कोई न चुनी जाए। कितने तरीके हैं?

From (14) chairs (7) chairs are to be selected and none of (5) broken chairs is selected. How many ways are there?

Explanation opens after your attempt
Correct Answer

A. (36)

Step 1

Concept

After removing (5) broken chairs (9) good chairs remain. The ways to choose (7) are \(\binom{9}{7}=36\).

Step 2

Why this answer is correct

The correct answer is A. (36). After removing (5) broken chairs (9) good chairs remain. The ways to choose (7) are \(\binom{9}{7}=36\).

Step 3

Exam Tip

(5) खराब कुर्सियां हटाने पर (9) अच्छी कुर्सियां बचती हैं। (7) चुनने के तरीके \(\binom{9}{7}=36\) हैं।

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(17) बिंदुओं से त्रिभुज बनाने हैं। यदि (9) बिंदु एक सीध में हैं तो केवल उन्हीं (9) बिंदुओं से बनने वाले असफल चयन कितने हैं?

Triangles are to be formed from (17) points. If (9) points are collinear then how many failed selections come only from those (9) points?

Explanation opens after your attempt
Correct Answer

B. \(\binom{9}{3}\)

Step 1

Concept

For a failed triangle (3) points are chosen from the (9) collinear points. So the number is \(\binom{9}{3}\).

Step 2

Why this answer is correct

The correct answer is B. \(\binom{9}{3}\). For a failed triangle (3) points are chosen from the (9) collinear points. So the number is \(\binom{9}{3}\).

Step 3

Exam Tip

असफल त्रिभुज के लिए (9) समरेखीय बिंदुओं में से (3) चुने जाते हैं। इसलिए संख्या \(\binom{9}{3}\) है।

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(16) संख्याओं में से (7) संख्याएं चुननी हैं जिनमें (3) निश्चित संख्याएं शामिल हों और (2) निश्चित संख्याएं शामिल न हों। कितने तरीके हैं?

From (16) numbers (7) numbers are to be selected with (3) fixed numbers included and (2) fixed numbers excluded. How many ways are there?

Explanation opens after your attempt
Correct Answer

C. (495)

Step 1

Concept

The (3) numbers are fixed and (2) are excluded. The remaining (4) numbers are chosen from (16-3-2=11), so \(\binom{11}{4}=330\).

Step 2

Why this answer is correct

The correct answer is C. (495). The (3) numbers are fixed and (2) are excluded. The remaining (4) numbers are chosen from (16-3-2=11), so \(\binom{11}{4}=330\).

Step 3

Exam Tip

(3) संख्याएं तय हैं और (2) हट गई हैं। बाकी (4) संख्याएं (11) में से \(\binom{11}{4}=330\) नहीं, बल्कि (16-3-2=11) से \(\binom{11}{4}=330\) होती हैं।

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(10) विषयों में से (5) विषय चुनने हैं। रसायन अवश्य चुना जाए, जीवविज्ञान न चुना जाए और गणित तथा भौतिकी दोनों साथ में न चुने जाएं। कितने तरीके हैं?

From (10) subjects (5) subjects are to be selected. Chemistry must be selected, biology must not be selected, and mathematics and physics must not both be selected together. How many ways are there?

Explanation opens after your attempt
Correct Answer

C. (55)

Step 1

Concept

Chemistry is fixed and biology is excluded. Choose the remaining (4) subjects from (8) and subtract \(\binom{6}{2}\) selections containing both mathematics and physics to get (55).

Step 2

Why this answer is correct

The correct answer is C. (55). Chemistry is fixed and biology is excluded. Choose the remaining (4) subjects from (8) and subtract \(\binom{6}{2}\) selections containing both mathematics and physics to get (55).

Step 3

Exam Tip

रसायन तय और जीवविज्ञान हट गया है। बाकी (4) विषय (8) में से चुनें और गणित-भौतिकी दोनों वाले \(\binom{6}{2}\) चयन घटाएं तो (55) मिलते हैं।

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(12) अलग-अलग अक्षरों में से (5) अक्षर चुनने हैं जिनमें (a) हो, (b) न हो और (c,d) में से ठीक एक अक्षर हो। कितने तरीके हैं?

From (12) distinct letters (5) letters are to be selected containing (a), not containing (b), and containing exactly one of (c,d). How many ways are there?

Explanation opens after your attempt
Correct Answer

B. (112)

Step 1

Concept

The letter (a) is fixed and (b) is excluded. Choose (1) from (c,d) and (3) from the remaining (8), so \(\binom{2}{1}\binom{8}{3}=112\).

Step 2

Why this answer is correct

The correct answer is B. (112). The letter (a) is fixed and (b) is excluded. Choose (1) from (c,d) and (3) from the remaining (8), so \(\binom{2}{1}\binom{8}{3}=112\).

Step 3

Exam Tip

(a) तय है और (b) हट गया है। (c,d) में से (1) और शेष (8) में से (3) चुनेंगे इसलिए \(\binom{2}{1}\binom{8}{3}=112\) है।

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(8) लाल, (9) नीली और (10) हरी गेंदों में से (2) लाल, (2) नीली और (2) हरी गेंद चुनने के कितने तरीके हैं?

From (8) red, (9) blue, and (10) green balls, how many ways are there to choose (2) red, (2) blue, and (2) green balls?

Explanation opens after your attempt
Correct Answer

C. (45360)

Step 1

Concept

Each color condition is counted separately. The ways are \(\binom{8}{2}\binom{9}{2}\binom{10}{2}=45360\).

Step 2

Why this answer is correct

The correct answer is C. (45360). Each color condition is counted separately. The ways are \(\binom{8}{2}\binom{9}{2}\binom{10}{2}=45360\).

Step 3

Exam Tip

हर रंग की शर्त अलग गिनी जाएगी। तरीके \(\binom{8}{2}\binom{9}{2}\binom{10}{2}=45360\) हैं।

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(13) फलों में से (6) फल चुनने हैं लेकिन (5) विशेष फलों में से ठीक (2) चुने जाएं। कितने तरीके हैं?

From (13) fruits (6) fruits are to be selected but exactly (2) of (5) special fruits are chosen. How many ways are there?

Explanation opens after your attempt
Correct Answer

B. (700)

Step 1

Concept

Choose (2) from the special fruits and (4) from the remaining (8). The ways are \(\binom{5}{2}\binom{8}{4}=700\).

Step 2

Why this answer is correct

The correct answer is B. (700). Choose (2) from the special fruits and (4) from the remaining (8). The ways are \(\binom{5}{2}\binom{8}{4}=700\).

Step 3

Exam Tip

विशेष फलों में से (2) और बाकी (8) में से (4) चुनेंगे। तरीके \(\binom{5}{2}\binom{8}{4}=700\) हैं।

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(12) मित्रों में से (6) को यात्रा के लिए चुनना है और (4) विशेष मित्रों में से कम से कम एक जाना चाहिए। कितने तरीके हैं?

From (12) friends (6) are to be selected for a trip and at least one of (4) special friends must go. How many ways are there?

Explanation opens after your attempt
Correct Answer

B. (896)

Step 1

Concept

Total ways are \(\binom{12}{6}=924\) and if no special friend goes then \(\binom{8}{6}=28\). Hence (924-28=896).

Step 2

Why this answer is correct

The correct answer is B. (896). Total ways are \(\binom{12}{6}=924\) and if no special friend goes then \(\binom{8}{6}=28\). Hence (924-28=896).

Step 3

Exam Tip

कुल \(\binom{12}{6}=924\) हैं और कोई विशेष मित्र न जाए तो \(\binom{8}{6}=28\) हैं। इसलिए (924-28=896) है।

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