एक विद्यालय में पहले सप्ताह (35) पौधे लगाए गए और हर अगले सप्ताह (8) पौधे अधिक लगाए गए। (16) सप्ताहों में कुल कितने पौधे लगेंगे?
In a school (35) plants were planted in the first week and (8) more plants were planted each next week. How many plants will be planted in (16) weeks?
#ap
#word-problem
#sum
#expert
A (1480)
B (1520)
C (1560)
D (1600)
Explanation opens after your attempt
Step 1
Concept
Total plants are (S_{16}=8[70+15(8)]=1520). Exam tip: treat the weekly increase as the common difference.
Step 2
Why this answer is correct
The correct answer is B. (1520). Total plants are (S_{16}=8[70+15(8)]=1520). Exam tip: treat the weekly increase as the common difference.
Step 3
Exam Tip
कुल पौधे (S_{16}=8[70+15(8)]=1520) हैं। परीक्षा में साप्ताहिक वृद्धि को सार्व अंतर मानें।
Login to save your score, XP, coins and progress. Login
एक समान्तर श्रेणी के पहले (12) पदों का योग (516) है और (12)वाँ पद (75) है। प्रथम पद क्या है?
The sum of the first (12) terms of an arithmetic progression is (516) and the (12)th term is (75). What is the first term?
#ap
#last-term
#sum
#expert
A (7)
B (9)
C (11)
D (13)
Explanation opens after your attempt
Step 1
Concept
Using (S_n=\frac{n}{2}(a+l)), (516=6(a+75)), so (a=11). Exam tip: when the last term is given, use the (a+l) form.
Step 2
Why this answer is correct
The correct answer is C. (11). Using (S_n=\frac{n}{2}(a+l)), (516=6(a+75)), so (a=11). Exam tip: when the last term is given, use the (a+l) form.
Step 3
Exam Tip
सूत्र (S_n=\frac{n}{2}(a+l)) से (516=6(a+75)) इसलिए (a=11)। परीक्षा में अंतिम पद दिया हो तो (a+l) वाला सूत्र तेज होता है।
Login to save your score, XP, coins and progress. Login
किसी समान्तर श्रेणी में प्रथम पद (7) और सार्व अंतर (5) है। यदि पहले (n) पदों का योग (1470) है तो (n) का मान क्या होगा?
In an arithmetic progression the first term is (7) and the common difference is (5). If the sum of the first (n) terms is (1470) then what is (n)?
#ap
#sum
#nth-sum
#expert
A (21)
B (24)
C (28)
D (30)
Explanation opens after your attempt
Step 1
Concept
Using (S_n=\frac{n}{2}[2a+(n-1)d]) gives (n=24). Exam tip: first reduce the equation to a simple quadratic.
Step 2
Why this answer is correct
The correct answer is B. (24). Using (S_n=\frac{n}{2}[2a+(n-1)d]) gives (n=24). Exam tip: first reduce the equation to a simple quadratic.
Step 3
Exam Tip
सूत्र (S_n=\frac{n}{2}[2a+(n-1)d]) लगाने पर (n=24) मिलता है। परीक्षा में पहले समीकरण को सरल वर्ग समीकरण में बदलें।
Login to save your score, XP, coins and progress. Login
किसी समांतर श्रेढ़ी का (n)वाँ पद \(a_n=7n-4\) है। पहले (80) पदों का योग ज्ञात कीजिए।
The (n)th term of an AP is \(a_n=7n-4\). Find the sum of the first (80) terms.
#nth term
#sum
#ap
A (22080)
B (22220)
C (22360)
D (22500)
Explanation opens after your attempt
Correct Answer
C. (22360)
Step 1
Concept
The first term is (3), and the (80)th term is (556), so the sum is (22360). Finding the first and last terms from \(a_n\) is an easy method.
Step 2
Why this answer is correct
The correct answer is C. (22360). The first term is (3), and the (80)th term is (556), so the sum is (22360). Finding the first and last terms from \(a_n\) is an easy method.
Step 3
Exam Tip
पहला पद (3) और (80)वाँ पद (556) है, इसलिए योग (22360) है। \(a_n\) से पहला और अंतिम पद निकालना आसान तरीका है।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(250,238,226,\ldots\) के पहले (30) पदों का योग ज्ञात कीजिए।
Find the sum of the first (30) terms of the AP \(250,238,226,\ldots\).
#decreasing sequence
#last term
#sum
A (2200)
B (2240)
C (2320)
D (2280)
Explanation opens after your attempt
Step 1
Concept
The last term is (-98), and \(S_{30}=2280\). Once the last term is found, (S_n=\frac{n}{2}(a+l)) is faster.
Step 2
Why this answer is correct
The correct answer is D. (2280). The last term is (-98), and \(S_{30}=2280\). Once the last term is found, (S_n=\frac{n}{2}(a+l)) is faster.
Step 3
Exam Tip
अंतिम पद (-98) है और \(S_{30}=2280\) है। अंतिम पद मिल जाए तो (S_n=\frac{n}{2}(a+l)) तेज रहता है।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(300,287,274,\ldots\) के पहले (35) पदों का योग ज्ञात कीजिए।
Find the sum of the first (35) terms of the AP \(300,287,274,\ldots\).
#decreasing ap
#negative difference
#sum
A (2715)
B (2735)
C (2755)
D (2765)
Explanation opens after your attempt
Step 1
Concept
Here (d=-13), and \(S_{35}=2765\). Do not forget the negative sign of the common difference in a decreasing AP.
Step 2
Why this answer is correct
The correct answer is D. (2765). Here (d=-13), and \(S_{35}=2765\). Do not forget the negative sign of the common difference in a decreasing AP.
Step 3
Exam Tip
यहाँ (d=-13) है और \(S_{35}=2765\) आता है। घटती श्रेढ़ी में सार्व अंतर का ऋणात्मक चिह्न न भूलें।
Login to save your score, XP, coins and progress. Login
किसी समांतर श्रेढ़ी में पहले (30) पदों का योग (3000) है और (30)वाँ पद (150) है। पहला पद ज्ञात कीजिए।
In an AP, the sum of the first (30) terms is (3000), and the (30)th term is (150). Find the first term.
#first term
#last term
#sum
#ap
A (45)
B (50)
C (55)
D (60)
Explanation opens after your attempt
Step 1
Concept
From (3000=15(a+150)), (a=50). Treat the (n)th term as the last term of the first (n) terms.
Step 2
Why this answer is correct
The correct answer is B. (50). From (3000=15(a+150)), (a=50). Treat the (n)th term as the last term of the first (n) terms.
Step 3
Exam Tip
(3000=15(a+150)) से (a=50) मिलता है। (n)वें पद को पहले (n) पदों का अंतिम पद मानें।
Login to save your score, XP, coins and progress. Login
एक समांतर श्रेढ़ी का पहला पद (x) और सार्व अंतर (3x-2) है। यदि पहले (12) पदों का योग (1128) है, तो (x) का मान क्या है?
The first term of an AP is (x), and the common difference is (3x-2). If the sum of the first (12) terms is (1128), what is the value of (x)?
#variable ap
#find x
#sum
A (5)
B (6)
C (7)
D (8)
Explanation opens after your attempt
Step 1
Concept
From (1128=6[2x+11(3x-2)]), (x=6). In variable-based questions, write (a) and (d) clearly first.
Step 2
Why this answer is correct
The correct answer is B. (6). From (1128=6[2x+11(3x-2)]), (x=6). In variable-based questions, write (a) and (d) clearly first.
Step 3
Exam Tip
(1128=6[2x+11(3x-2)]) से (x=6) मिलता है। चर वाले प्रश्न में पहले (a) और (d) स्पष्ट लिखें।
Login to save your score, XP, coins and progress. Login
किसी समांतर श्रेढ़ी का (n)वाँ पद \(a_n=5n-2\) है। पहले (70) पदों का योग ज्ञात कीजिए।
The (n)th term of an AP is \(a_n=5n-2\). Find the sum of the first (70) terms.
#nth term
#sum
#ap
A (12110)
B (12180)
C (12355)
D (12285)
Explanation opens after your attempt
Correct Answer
D. (12285)
Step 1
Concept
The first term is (3), and the (70)th term is (348), so the sum is (12285). Finding the first and last terms from \(a_n\) is an easy method.
Step 2
Why this answer is correct
The correct answer is D. (12285). The first term is (3), and the (70)th term is (348), so the sum is (12285). Finding the first and last terms from \(a_n\) is an easy method.
Step 3
Exam Tip
पहला पद (3) और (70)वाँ पद (348) है, इसलिए योग (12285) है। \(a_n\) से पहले और अंतिम पद निकालना आसान तरीका है।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(140,132,124,\ldots\) के पहले (25) पदों का योग ज्ञात कीजिए।
Find the sum of the first (25) terms of the AP \(140,132,124,\ldots\).
#decreasing ap
#last term
#sum
A (1040)
B (1060)
C (1080)
D (1100)
Explanation opens after your attempt
Step 1
Concept
The last term is (-52), and \(S_{25}=1100\). Even in a decreasing AP, (S_n=\frac{n}{2}(a+l)) is useful.
Step 2
Why this answer is correct
The correct answer is D. (1100). The last term is (-52), and \(S_{25}=1100\). Even in a decreasing AP, (S_n=\frac{n}{2}(a+l)) is useful.
Step 3
Exam Tip
अंतिम पद (-52) है और \(S_{25}=1100\) है। घटती श्रेढ़ी में भी (S_n=\frac{n}{2}(a+l)) उपयोगी है।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(160,151,142,\ldots\) के पहले (22) पदों का योग ज्ञात कीजिए।
Find the sum of the first (22) terms of the AP \(160,151,142,\ldots\).
#decreasing ap
#negative difference
#sum
A (1397)
B (1419)
C (1463)
D (1441)
Explanation opens after your attempt
Step 1
Concept
Here (d=-9), and the formula gives \(S_{22}=1441\). In a decreasing AP, write the common difference as negative.
Step 2
Why this answer is correct
The correct answer is D. (1441). Here (d=-9), and the formula gives \(S_{22}=1441\). In a decreasing AP, write the common difference as negative.
Step 3
Exam Tip
यहाँ (d=-9) है और सूत्र से \(S_{22}=1441\) मिलता है। घटती श्रेढ़ी में सार्व अंतर ऋणात्मक लिखें।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(-12,-5,2,\ldots,184\) का योग ज्ञात कीजिए।
Find the sum of the AP \(-12,-5,2,\ldots,184\).
#finite ap
#last term
#sum
A (2449)
B (2472)
C (2517)
D (2494)
Explanation opens after your attempt
Step 1
Concept
First, (184=-12+(n-1)7) gives (n=29), and the sum is (2494). When the last term is given, find (n) first.
Step 2
Why this answer is correct
The correct answer is D. (2494). First, (184=-12+(n-1)7) gives (n=29), and the sum is (2494). When the last term is given, find (n) first.
Step 3
Exam Tip
पहले (184=-12+(n-1)7) से (n=29) मिलता है और योग (2494) है। अंतिम पद दिया हो तो पहले (n) निकालें।
Login to save your score, XP, coins and progress. Login
किसी समांतर श्रेढ़ी में पहले (25) पदों का योग (1625) है और (25)वाँ पद (113) है। पहला पद ज्ञात कीजिए।
In an AP, the sum of the first (25) terms is (1625), and the (25)th term is (113). Find the first term.
#first term
#last term
#sum
#ap
A (17)
B (15)
C (19)
D (21)
Explanation opens after your attempt
Step 1
Concept
From (1625=\frac{25}{2}(a+113)), (a=17). Treat the (n)th term as the last term of the first (n) terms.
Step 2
Why this answer is correct
The correct answer is A. (17). From (1625=\frac{25}{2}(a+113)), (a=17). Treat the (n)th term as the last term of the first (n) terms.
Step 3
Exam Tip
(1625=\frac{25}{2}(a+113)) से (a=17) मिलता है। (n)वें पद को पहले (n) पदों का अंतिम पद मानें।
Login to save your score, XP, coins and progress. Login
एक समांतर श्रेढ़ी का पहला पद (x) और सार्व अंतर (2x+1) है। यदि पहले (10) पदों का योग (445) है, तो (x) का मान क्या है?
The first term of an AP is (x), and the common difference is (2x+1). If the sum of the first (10) terms is (445), what is the value of (x)?
#variable ap
#find x
#sum
A (2)
B (3)
C (5)
D (4)
Explanation opens after your attempt
Step 1
Concept
From (445=5[2x+9(2x+1)]), (x=4). In variable-based questions, write (a) and (d) clearly first.
Step 2
Why this answer is correct
The correct answer is D. (4). From (445=5[2x+9(2x+1)]), (x=4). In variable-based questions, write (a) and (d) clearly first.
Step 3
Exam Tip
(445=5[2x+9(2x+1)]) से (x=4) मिलता है। चर वाले प्रश्न में पहले (a) और (d) स्पष्ट लिखें।
Login to save your score, XP, coins and progress. Login
किसी समांतर श्रेढ़ी का (n)वाँ पद \(a_n=6n+5\) है। पहले (60) पदों का योग ज्ञात कीजिए।
The (n)th term of an AP is \(a_n=6n+5\). Find the sum of the first (60) terms.
#nth term
#sum
#ap
A (11280)
B (11160)
C (11400)
D (11520)
Explanation opens after your attempt
Correct Answer
A. (11280)
Step 1
Concept
The first term is (11), and the (60)th term is (365), so the sum is (11280). Finding the first and last terms from \(a_n\) is an easy method.
Step 2
Why this answer is correct
The correct answer is A. (11280). The first term is (11), and the (60)th term is (365), so the sum is (11280). Finding the first and last terms from \(a_n\) is an easy method.
Step 3
Exam Tip
पहला पद (11) और (60)वाँ पद (365) है, इसलिए योग (11280) है। \(a_n\) से पहले और अंतिम पद निकालना आसान तरीका है।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(95,89,83,\ldots\) के पहले (20) पदों का योग ज्ञात कीजिए।
Find the sum of the first (20) terms of the AP \(95,89,83,\ldots\).
#decreasing ap
#last term
#sum
A (730)
B (760)
C (790)
D (820)
Explanation opens after your attempt
Step 1
Concept
The last term is (-19), and \(S_{20}=760\). Even in a decreasing AP, (S_n=\frac{n}{2}(a+l)) is useful.
Step 2
Why this answer is correct
The correct answer is B. (760). The last term is (-19), and \(S_{20}=760\). Even in a decreasing AP, (S_n=\frac{n}{2}(a+l)) is useful.
Step 3
Exam Tip
अंतिम पद (-19) है और \(S_{20}=760\) है। घटती श्रेढ़ी में भी (S_n=\frac{n}{2}(a+l)) उपयोगी है।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(120,113,106,\ldots\) के पहले (25) पदों का योग ज्ञात कीजिए।
Find the sum of the first (25) terms of the AP \(120,113,106,\ldots\).
#decreasing ap
#negative difference
#sum
A (850)
B (875)
C (900)
D (925)
Explanation opens after your attempt
Step 1
Concept
Here (d=-7), and the formula gives \(S_{25}=900\). In a decreasing AP, write the common difference as negative.
Step 2
Why this answer is correct
The correct answer is C. (900). Here (d=-7), and the formula gives \(S_{25}=900\). In a decreasing AP, write the common difference as negative.
Step 3
Exam Tip
यहाँ (d=-7) है और सूत्र से \(S_{25}=900\) मिलता है। घटती श्रेढ़ी में सार्व अंतर ऋणात्मक लिखें।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(-6,1,8,\ldots,169\) का योग ज्ञात कीजिए।
Find the sum of the AP \(-6,1,8,\ldots,169\).
#finite ap
#last term
#sum
A (2074)
B (2096)
C (2119)
D (2142)
Explanation opens after your attempt
Step 1
Concept
First, (169=-6+(n-1)7) gives (n=26), and the sum is (2119). When the last term is given, find (n) first.
Step 2
Why this answer is correct
The correct answer is C. (2119). First, (169=-6+(n-1)7) gives (n=26), and the sum is (2119). When the last term is given, find (n) first.
Step 3
Exam Tip
पहले (169=-6+(n-1)7) से (n=26) मिलता है और योग (2119) है। अंतिम पद दिया हो तो पहले (n) निकालें।
Login to save your score, XP, coins and progress. Login
किसी समांतर श्रेढ़ी में पहले (20) पदों का योग (740) है और (20)वाँ पद (60) है। पहला पद ज्ञात कीजिए।
In an AP, the sum of the first (20) terms is (740), and the (20)th term is (60). Find the first term.
#first term
#last term
#sum
#ap
A (10)
B (14)
C (18)
D (22)
Explanation opens after your attempt
Step 1
Concept
From (740=10(a+60)), (a=14). When the (n)th term is given, use it as the last term for the first (n) terms.
Step 2
Why this answer is correct
The correct answer is B. (14). From (740=10(a+60)), (a=14). When the (n)th term is given, use it as the last term for the first (n) terms.
Step 3
Exam Tip
(740=10(a+60)) से (a=14) मिलता है। जब (n)वाँ पद दिया हो तो उसे अंतिम पद की तरह इस्तेमाल करें।
Login to save your score, XP, coins and progress. Login
एक समांतर श्रेढ़ी का पहला पद (x) और सार्व अंतर (x+2) है। यदि पहले (10) पदों का योग (365) है, तो (x) का मान क्या है?
The first term of an AP is (x), and the common difference is (x+2). If the sum of the first (10) terms is (365), what is the value of (x)?
#variable ap
#find x
#sum
A (5)
B (6)
C (7)
D (8)
Explanation opens after your attempt
Step 1
Concept
From (365=5[2x+9(x+2)]), (x=5). In variable-based questions, write (a) and (d) clearly first.
Step 2
Why this answer is correct
The correct answer is A. (5). From (365=5[2x+9(x+2)]), (x=5). In variable-based questions, write (a) and (d) clearly first.
Step 3
Exam Tip
(365=5[2x+9(x+2)]) से (x=5) मिलता है। चर वाले प्रश्न में पहले (a) और (d) को साफ लिखें।
Login to save your score, XP, coins and progress. Login
किसी समांतर श्रेढ़ी का (n)वाँ पद \(a_n=4n-1\) है। पहले (50) पदों का योग ज्ञात कीजिए।
The (n)th term of an AP is \(a_n=4n-1\). Find the sum of the first (50) terms.
#nth term
#sum
#ap
A (5050)
B (5000)
C (5100)
D (5150)
Explanation opens after your attempt
Step 1
Concept
The first term is (3), and the (50)th term is (199), so the sum is (5050). Finding the first and last terms from \(a_n\) is an easy method.
Step 2
Why this answer is correct
The correct answer is A. (5050). The first term is (3), and the (50)th term is (199), so the sum is (5050). Finding the first and last terms from \(a_n\) is an easy method.
Step 3
Exam Tip
पहला पद (3) और (50)वाँ पद (199) है, इसलिए योग (5050) है। \(a_n\) से पहले और अंतिम पद निकालना आसान तरीका है।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(12,18,24,\ldots,192\) का योग ज्ञात कीजिए।
Find the sum of the AP \(12,18,24,\ldots,192\).
#finite ap
#last term
#sum
A (3144)
B (3156)
C (3162)
D (3180)
Explanation opens after your attempt
Step 1
Concept
First, (192=12+(n-1)6) gives (n=31), and the sum is (3162). When the last term is given, find the number of terms first.
Step 2
Why this answer is correct
The correct answer is C. (3162). First, (192=12+(n-1)6) gives (n=31), and the sum is (3162). When the last term is given, find the number of terms first.
Step 3
Exam Tip
पहले (192=12+(n-1)6) से (n=31) मिलता है और योग (3162) है। अंतिम पद हो तो पहले पदों की संख्या निकालें।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(8,13,18,\ldots,83\) का योग ज्ञात कीजिए।
Find the sum of the AP \(8,13,18,\ldots,83\).
#finite ap
#last term
#sum
A (720)
B (728)
C (736)
D (744)
Explanation opens after your attempt
Step 1
Concept
First find (n): (83=8+(n-1)5), so (n=16) and the sum is (728). When the last term is given, find the number of terms first.
Step 2
Why this answer is correct
The correct answer is B. (728). First find (n): (83=8+(n-1)5), so (n=16) and the sum is (728). When the last term is given, find the number of terms first.
Step 3
Exam Tip
पहले (n) निकालें: (83=8+(n-1)5), इसलिए (n=16) और योग (728) है। अंतिम पद होने पर पहले पदों की संख्या निकालें।
Login to save your score, XP, coins and progress. Login
यदि पहले (n) प्राकृतिक संख्याओं का योग (465) है, तो (n) क्या होगा?
If the sum of the first (n) natural numbers is (465), what is (n)?
#natural numbers
#sum
#ap
A (28)
B (29)
C (30)
D (31)
Explanation opens after your attempt
Step 1
Concept
From (\frac{n(n+1)}{2}=465), (n=30). The sum of natural numbers is a special case of AP.
Step 2
Why this answer is correct
The correct answer is C. (30). From (\frac{n(n+1)}{2}=465), (n=30). The sum of natural numbers is a special case of AP.
Step 3
Exam Tip
(\frac{n(n+1)}{2}=465) से (n=30) आता है। प्राकृतिक संख्याओं का योग भी समांतर श्रेढ़ी का विशेष रूप है।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(100,95,90,\ldots\) के पहले (12) पदों का योग ज्ञात कीजिए।
Find the sum of the first (12) terms of the AP \(100,95,90,\ldots\).
#decreasing sequence
#last term
#sum
A (870)
B (880)
C (890)
D (900)
Explanation opens after your attempt
Step 1
Concept
The last term is (45), so (S_{12}=\frac{12}{2}(100+45)=870). Once the last term is found, the sum is quick.
Step 2
Why this answer is correct
The correct answer is A. (870). The last term is (45), so (S_{12}=\frac{12}{2}(100+45)=870). Once the last term is found, the sum is quick.
Step 3
Exam Tip
अंतिम पद (45) है, इसलिए (S_{12}=\frac{12}{2}(100+45)=870)। अंतिम पद मिल जाए तो योग तेजी से निकलेगा।
Login to save your score, XP, coins and progress. Login
समांतर श्रेढ़ी \(31,28,25,\ldots\) के पहले (20) पदों का योग ज्ञात कीजिए।
Find the sum of the first (20) terms of the AP \(31,28,25,\ldots\).
#decreasing ap
#negative terms
#sum
A (50)
B (55)
C (60)
D (65)
Explanation opens after your attempt
Step 1
Concept
Here the last term is (-26), and \(S_{20}=50\). In a decreasing AP, the sum can become quite small.
Step 2
Why this answer is correct
The correct answer is A. (50). Here the last term is (-26), and \(S_{20}=50\). In a decreasing AP, the sum can become quite small.
Step 3
Exam Tip
यहाँ अंतिम पद (-26) है और \(S_{20}=50\) मिलता है। घटती श्रेढ़ी में योग बहुत छोटा भी हो सकता है।
Login to save your score, XP, coins and progress. Login
यदि किसी समांतर श्रेढ़ी का पहला पद (11), अंतिम पद (71) और योग (574) है, तो पदों की संख्या क्या है?
If an AP has first term (11), last term (71), and sum (574), what is the number of terms?
#find number of terms
#last term
#sum
A (12)
B (13)
C (14)
D (15)
Explanation opens after your attempt
Step 1
Concept
From (\frac{n}{2}(11+71)=574), (n=14). When the last term is given, the common difference is not needed.
Step 2
Why this answer is correct
The correct answer is C. (14). From (\frac{n}{2}(11+71)=574), (n=14). When the last term is given, the common difference is not needed.
Step 3
Exam Tip
(\frac{n}{2}(11+71)=574) से (n=14) मिलता है। अंतिम पद दिए होने पर सार्व अंतर की जरूरत नहीं होती।
Login to save your score, XP, coins and progress. Login
समांतर श्रेणी \(90,84,78,\ldots\) के पहले (6) पदों का योग कितना होगा?
What will be the sum of the first (6) terms of the arithmetic progression \(90,84,78,\ldots\)?
#decreasing_ap
#sum
#six_terms
A (440)
B (450)
C (460)
D (470)
Explanation opens after your attempt
Step 1
Concept
The sixth term is (60), so (S_6=\frac{6}{2}(90+60)=450). In decreasing order, calculate the last term carefully.
Step 2
Why this answer is correct
The correct answer is B. (450). The sixth term is (60), so (S_6=\frac{6}{2}(90+60)=450). In decreasing order, calculate the last term carefully.
Step 3
Exam Tip
छठा पद (60) है, इसलिए (S_6=\frac{6}{2}(90+60)=450)। घटते क्रम में अंतिम पद की गणना ध्यान से करें।
Login to save your score, XP, coins and progress. Login
पहले (28) प्राकृतिक संख्याओं का योग ज्ञात कीजिए।
Find the sum of the first (28) natural numbers.
#natural_numbers
#sum
#ap
A (386)
B (396)
C (406)
D (416)
Explanation opens after your attempt
Step 1
Concept
\(\frac{28\times29}{2}=406\), so the sum is (406). The natural-number sum formula gives a quick answer.
Step 2
Why this answer is correct
The correct answer is C. (406). \(\frac{28\times29}{2}=406\), so the sum is (406). The natural-number sum formula gives a quick answer.
Step 3
Exam Tip
\(\frac{28\times29}{2}=406\), इसलिए योग (406) है। प्राकृतिक संख्याओं का योग सूत्र जल्दी उत्तर देता है।
Login to save your score, XP, coins and progress. Login
पहले (17) सम प्राकृतिक संख्याओं का योग ज्ञात कीजिए।
Find the sum of the first (17) even natural numbers.
#even_numbers
#sum
#ap
A (296)
B (306)
C (316)
D (326)
Explanation opens after your attempt
Step 1
Concept
The sum of the first (n) even numbers is (n(n+1)), so \(17\times18=306\). Do not confuse (n) with the last even number.
Step 2
Why this answer is correct
The correct answer is B. (306). The sum of the first (n) even numbers is (n(n+1)), so \(17\times18=306\). Do not confuse (n) with the last even number.
Step 3
Exam Tip
पहले (n) सम संख्याओं का योग (n(n+1)) है, इसलिए \(17\times18=306\)। (n) को अंतिम सम संख्या न समझें।
Login to save your score, XP, coins and progress. Login
