Two numbers are in the ratio 3:4. The product of their HCF and LCM is 2028.…

2018

Two numbers are in the ratio 3:4. The product of their HCF and LCM is 2028. The sum of the numbers will be:

  1. A.

    72

  2. B.

    86

  3. C.

    68

  4. D.

    91

Attempted by 16 students.

Show answer & explanation

Correct answer: D

Concept

For any two positive integers a and b, HCF(a, b) × LCM(a, b) = a × b.

If two numbers are in the ratio m:n, write them as mk and nk, where k is their common scale factor.

Application

  1. Write the numbers as 3k and 4k.

  2. Use the product identity: (3k)(4k) = 2028, so 12k2 = 2028.

  3. Divide by 12: k2 = 169. Since the numbers are positive, k = 13.

  4. Therefore, the numbers are 3 × 13 = 39 and 4 × 13 = 52, and their sum is 39 + 52 = 91.

Cross-check

The HCF of 39 and 52 is 13 and their LCM is 156; 13 × 156 = 2028, so both the ratio and the product condition are satisfied.

Explore the full course: Rssb Senior Computer Instructor

Loading lesson…