Question

which of the following is not a prime number? A-3163, B-263,C-157,AND D-1057

Answer 1

We know that the prime numbers are divisible only by 1 and by itself.
Those numbers are: 2, 3, 5, 7, 11, 13,...
And also:
1057 : 7 = 151
So number 1057 is divisible also by 7 and 151.
Answer:
D - 1057 is not a prime number.