The smallest number which when decreased by 3 is divisible by 15, 25 and 55, is:

Correct option is A

Given:

We are to find the smallest number which when decreased by 3 is divisible by 15, 25, and 55.

Solution:

Prime factorizations:

15 = 3 × 5

25 = 5²

55 = 5 × 11

LCM(15, 25, 55) = 3 × 5² × 111 = 3 × 25 × 11 = 825

Thus, the smallest number is 825 + 3 = 828