A and B are two number when divided by 7 leaves a remainder 3 and 5. What will be the remainder when A-B is divided by 7 ?

A = 7x + 3,
B = 7y + 5
A – B = 7(x – y) – 2
A – B = 7(x – y) – 7 + 7 – 2 [By adding -7 and +7] A – B = 7(x – y – 1) + 5
As seen above, if we divide A-B by 7, the remainder will be 5.