Answer:
3/20 or 15%
Step-by-step explanation:
Out of 1,2,3,4, and 5, there are 3 prime numbers. This makes the odds of selecting one of those prime numbers 3/5. Then, saying that he does pick a prime number and discards that card, there are now four cards, one of them being the number one. His chances of selecting this card is 1/4.
To find the probability you need to multiply the two probabilities together.
3/5 times 1/4 is 3/20.
So your answer is 3/20 or 15%.