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

you just switch the numbers basically so it would be 3/17