Question

There are two spinners. Each spinner has 10 equal sectors labeled with the numbers 1 through 10.

How many outcomes show a prime number on the first spinner and a composite number on the second spinner?



9

20

25

100

Answer 1

There are 4 prime numbers from 1 to 10: 2, 3, 5, and 7. This means that there are 4 ways to choose the first outcome. There are 5 composite numbers from 1 to 10: 4, 6, 8, 9, and 10 (1 is just 1). So, you just multiply the two numbers together because each depends on each: 4 * 5 = 20 outcomes.