Question

There are 18 number-tiles in a jar, each marked with a different number from 1-18. If you pull out one tile at random, what is the probability that the number you pull will be an even number or a prime number?
show all your work

0.944

0.722

0.889

Answer 1

To calculate the probability that the number you pull will be an even number or a prime number, we first need to determine how many numbers in the set are even, prime, or both.

There are 9 even numbers in the set (2, 4, 6, 8, 10, 12, 14, 16, 18) and 8 prime numbers in the set (2, 3, 5, 7, 11, 13, 17).

However, notice that the number 2 is both an even number and a prime number. So it is included in both counts. Therefore, there are 8 numbers that are only even, 7 numbers that are only prime, and 1 number that is both.

So, the total number of numbers that are even or prime is 8 + 7 - 1 = 14.

Since there are 18 total numbers in the jar, the probability of pulling out an even number or a prime number is 14/18 = 0.778.

Therefore, the probability that the number you pull will be an even number or a prime number is approximately 0.778 or 77.8%.