Question

Help Johny find the billiard ball with a prime number on it.

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

The factor pairs of 6 are:
1 x 6
2 x 3
3 x 2
6 x 1
Thus, the factors of 6 are: 1, 2, 3, 6

The factor pairs of 19 are:
1 x 19
19 x 1
Thus, the factors of 19 are: 1, 19

The factor pairs of 12 are:
1 x 12
2 x 6
3 x 4
4 x 3
6 x 2
12 x 1
Thus, the factors of 12 are: 1, 2, 3, 4, 6, 12

The factor pairs of 15 are:
1 x 15
3 x 5
5 x 3
15 x 1
Thus, the factors of 15 are: 1, 3, 5, 15

Prime numbers are numbers with exactly two factors, 1 and the number itself.
From the steps, we can see that 19 is a prime number since its factors are 1 and 19.

Hence, the required billiard ball is the one with 19 written on it.