Question

If 123xy is divisible by 40, then the value in place of x+y is:
a) 4
b) 3
c) 7
d) 1

Answer 1

Maybe the correct answer is 3

Answer 2

Answer:

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

Here, lets take option a) first.

Let us take option a), x +y = 4, then the sum becomes 1+2+3+4 = 10, which is divisible by 40. Hence, this is the correct option.

Lets check options as well.

option b) - then the sum becomes 9, which is clearly not divisible by 40.

Option c) - Sun becomes 13, again not divisible by 40

Option d) - Sum becomes 7, again not divisible by 40.

The correct answer is option a , that is , 40.