Question

123xy is divisible by 40 then find the value of x+y​

Answer 1

To answer the question, you must know the rules of divisibility.

The number will be divisible by 40 when it is divisible by 4 and 10.

We know that 10 = 5*2

So, the number must be divisible by 5 and 2.

Rules of divisibility for:

a) 4 - the last two digits of the number must be divisible by 4

b) 5 - the last digit is either '5' or '0'

c) 2 - the number is even