Answer :
Not because 143 is divided by 11 and by 13.
143 = 13 × 11
143 has 4 divisors:
{ 1, 11, 13, 143}
The prime number has only 2 divisors: 1 and itself.
143 is composite. To be prime it has to have only 2 divisors i.e it's self and one but since it has 4 divisors ( 143, 1, 11 and 13) it is composite.
