Question

Let S be a set of first fourteen natural numbers.
The possible number of pairs (a, b), where a, b belongs to S
and a is not equal to b such that ab leaves remainder 1 when
divided by 15, is​

Answer 1

Step-by-step explanation:

15divede31 remainder1

Answer 2

Step-by-step explanation:

So divide 15 and 31 you will get 1 as remainder.

31/15=1