Question

Find the least number which when divides 35, 56 and 91 leaves the same remainder 7 in each case.

Answer 1

Least number which can be divided by 35, 56 and 91 is LCM of 35, 56 and 91.

Prime factorisation of 35, 56 and 91 is:

35 = 5 × 7

56 = 2³ × 7

91 = 7 × 13

LCM = product of greatest power of each prime factor involved in the numbers = 2³ × 5 × 7 × 13 = 3640

Least number which can be divided by 35, 56 and 91 is 3640.

Least number which when divided by 35, 56 and 91 leaves the same remainder 7 is 3640 + 7 = 3647.

Thus, the required number is 3647.