Question

You pick a card at random.

2
3
4
5
6
7
8
9


What is P(not prime)?

Write your answer as a percentage.

Answer 1

To find the probability of picking a card that is not prime from the given set of numbers, we first identify which numbers are prime and which are not:

The numbers given are: 2, 3, 4, 5, 6, 7, 8, 9.

**Identifying prime numbers:**
- 2 is prime.
- 3 is prime.
- 4 is not prime (divisible by 2).
- 5 is prime.
- 6 is not prime (divisible by 2 and 3).
- 7 is prime.
- 8 is not prime (divisible by 2).
- 9 is not prime (divisible by 3).

**Prime numbers:** 2, 3, 5, 7 (4 numbers)
**Not prime numbers:** 4, 6, 8, 9 (4 numbers)

**Total number of cards:** 8
**Number of not prime cards:** 4

Now, we can calculate the probability:

\[
P(\text{not prime}) = \frac{\text{Number of not prime numbers}}{\text{Total number of cards}} = \frac{4}{8} = 0.5
\]

To express this as a percentage:

\[
P(\text{not prime}) = 0.5 \times 100\% = 50\%
\]

Thus, the probability of picking a card that is not prime is **50%**.