Question

The remainder on dividing given integers a and b by 7 are respectively 5 and 4. Then,
the remainder when ab is divided by 7 is
A 5
B. 4​

Answer 1

Answer:

A. 5 is answer with divided by 7

Answer 2

Answer:

The number would be in the form of (7X + 4) as when this number is divide by 7, will give remainder 4.

Now, we will try hit and trial method to obtained the number.

Put, X = 17, then

7X + 4 = 7 *17 + 4 = 119 + 4 = 123.

Now, when

123 divided by 7, gievs quotient = 17, remainder = 4.

17 divided by 5, quotient = 3, remainder = 2

3 divide by 4 gives remainder 3.

So far first condition satisfied . Now,

123 divide by 8, quotient = 15, remainder = 3

15 divided by 5, quotient = 3, remainder = 0

3 divided by 6, remainder = 3.