Muft Shiksha
Update

Muft Shiksha™ एक 100% Free Education Portal है 🇮🇳, जिसका उद्देश्य Class 9–12 के हर विद्यार्थी तक High-Quality Education को पूरी तरह मुफ्त पहुँचाना है। 🇮🇳 हम मानते हैं कि अच्छी शिक्षा किसी student की आर्थिक स्थिति पर निर्भर नहीं होनी चाहिए। 🇮🇳 हर विद्यार्थी को वही Quality Study Material, MCQs, Quizzes, Exam Preparation, Concept-Based Learning और Bilingual Support मिलना चाहिए, जो आमतौर पर महंगी Coaching या Premium Platforms में मिलता है। Muft Shiksha™ 🇮🇳 इसी सोच के साथ बनाया गया है

Subjects
Class 10MathematicsReal NumbersHCF and LCM using prime factorisationExpertLevel 11
0 reads0 ratings0 helpful

The HCF of two numbers is (21) and their LCM is (2310). How many unordered pairs are possible?

Advertisement

Answer and explanation

Correct answer: (4)

Step 1: Let the numbers be (21m) and (21n), where (m) and (n) are coprime. Step 2: (21mn=2310), so (mn=110=2\times5\times11). Three distinct prime factors give (4) unordered coprime pairs. Step 3: Do not count the reversed order again.

Related tags

Real-NumbersHcf-LcmPair-Count

Frequently asked questions

What is the correct answer to this question?

(4)

Why is this the correct answer?

Step 1: Let the numbers be (21m) and (21n), where (m) and (n) are coprime. Step 2: (21mn=2310), so (mn=110=2\times5\times11). Three distinct prime factors give (4) unordered coprime pairs. Step 3: Do not count the reversed order again.

Which subject and chapter does this question cover?

This is a Class 10 Mathematics question. Chapter: Real Numbers. Topic: HCF and LCM using prime factorisation.

Was this question useful?

No ratings yetWrite a review / Rate this question

Student Reviews

No published reviews yet.

KEEP PRACTISING

10 more MCQs
  1. 1If the product of two numbers is 3780 and their LCM is 315, what is their HCF?
  2. 2What is the HCF of (18) and (24) using prime factorisation?
  3. 3What is the LCM of (18) and (24) using prime factorisation?
  4. 4What is the HCF of (40) and (60)?
  5. 5What is the LCM of (40) and (60)?
  6. 6What will be the HCF of (45) and (75)?
  7. 7What will be the LCM of (45) and (75)?
  8. 8Which is the HCF of (32) and (48)?
  9. 9Which is the LCM of (32) and (48)?
  10. 10What is the HCF of (27) and (36)?
Advertisement