Patty rolls a six-sided number die 120 times. How many times should she expect to roll a
prime number?

Answer is 60 times.
Explanation:
Prime numbers in a die are 2, 3 and 5 (i.e. 3 numbers)
Total outcomes can be 1, 2, 3, 4, 5 and 6 (i.e. 6 numbers)
Probability
= Number of preferred outcomes/ Total number of outcomes
= 3/6
= 1/2
= 0.5
Probability of getting a prime number while throwing the dice 120 times
= 0.5 × 120
= 60 times