Question

If AB is divisible by 5 but not divisible by 2 and BA is divisible 3. Then which of the following is the possible values of A and B?

• A. (x-2)(x-5)= – 7x + 10
• B. (x+2) (x-2) = - 4
• C. A = 7,B = 5
• D. A = 4,B = 0

Answer 1

The correct option is B

(x+2) (x-2) = - 4

AB is divisible by 5. Thus, B should be either 0 or 5. But since AB is not divisible by 2, B is surely 5.
Since BA is divisible by 3, A + B should also be divisible by 3.
But B is 5. Thus A + 5 should also be divisible by 3.
Among the options, A + 5 will be divisible by 3 only if A = 4.