# Sally is spinning a spinner with the numbers 1-8 with equal size sections. If she spins the spinner 1 time, what is the probability that she will land on a prime number? Also, find the complement of this event.

##### 1 Answer

May 1, 2018

**not** landing on a prime)

#### Explanation:

(Assuming 1-8 means both are included)

There are 4 primes in the list, out of a total 8 numbers. Thus the probability is the number of favourable outcomes(4) divided by total possible outcomes(8). This equals one-half.

The probability of the complement of any event is

The complement of the prime set is **not** the set of composite numbers(as 1 is considered neither prime nor composite). Thus the complement is the set of non-prime numbers from 1 to 8.