Question

a lottery game has balls numbered 1 through 21. what is the probability of selecting a ball with a prime number on it or a 10

Answer 1

`(9)/(21)`

Explanation:

→ List the prime numbers between 1 and 21

2, 3, 5, 7, 11, 13, 17 and 19

→ Count how many ball that is

8 balls

→ Remember in the question it says "what is the probability of selecting a ball with a prime number on it or a 10"

8 balls + 1 ball (the one with the number 10)

→ 9 balls overall over a total of 21

Answer 2

3/7

Explanation:

The prime numbers that lie between 1 and 21 are 2,3,5,7,11,13,17, and 19. These 8 balls, plus the 10-ball comes to a total of 9 balls that could be picked out of the 21. Therefore, the probability of picking one of these balls is 9/21 or 3/7