Question

What is the smallest no which when increase by 11 is exactly divisible by 15, 20 and 54.?

Answer 1

First we have to find the smallest number that is divisible by 15, 20 and 54.
So we have to find the LCM of 15,20 and 54.

54  = 2 * 27
= 2 * 3 * 3 * 3

20 = 2 * 2 * 5

15 = 3 * 5

LCM = 3 * 5 * 2 * 3 * 3 * 2 
= 540

Now,
The smallest number which when increased by 11 gives a number exactly divisible by 15,20 & 54 be x

Therefore,

x + 11 = 540

x = 540 - 11

x = 529.

∴ 529 is the smallest no which when increase by 11 is exactly divisible by 15, 20 and 54.