Question

the smallest number which when increased by 15 is exactly divisible by 100 and 20

Answer 1

First take the LCM of 100 and 20.
It comes out to be 100.
Now we know that 100 is exactly divisible by both 20 and 100, so 
required number+15 must be= 100
Let the req no. be x 
x+15 = 100
x=85

85 is the required number.

Answer 2

85 is the number.

Step-by-step explanation:

We first find LCM of 100 and 20 which would be 100 because it will give the numbers divisible by both.

Let the number be x.

Then$(x + 15)$ should be divisible by 100.

The smallest number divisible by 100 is 100 itself.

So, $x + 15 = 100$

$x = 100 -15 = 85$

Hence, the number is 85.