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?
A)0.833
B)0.889
C)0.722
D)0.944
To find the probability that the number pulled will be an even number or a prime number, we first need to find how many even numbers and prime numbers are there between 1 and 18:
Even numbers between 1 and 18: 2, 4, 6, 8, 10, 12, 14, 16, 18 (9 numbers)
Prime numbers between 1 and 18: 2, 3, 5, 7, 11, 13, 17 (7 numbers)
There is an overlap between even numbers and prime numbers where 2 appears in both lists. To avoid counting it twice, we will only count it once.
Therefore, the total number of numbers that are either even or prime is 9 (even numbers) + 7 (prime numbers) - 1 (overlap) = 15.
The total number of number-tiles is 18.
So, the probability is: 15/18 = 5/6 = 0.833
Therefore, the answer is A) 0.833.