What is the probability of rolling a 5 on a number cube 8 or fewer times in 20 rolls?

0.911
0.997
0.526
0.003

Use the Binomial distribution.

Let X be the event of getting a 5. The probability of getting a 5 in one throw is 1/6.

So, X ~ B(20, 1/6)

Find P(X < 9)