Question 1055808
Binomial Distribution:  p = .05 , n = 250
Using TI Calculator
P(x <= 15) = binomcdf(250, .005, 15) = .8113
Recommend Using stattrek.com to check  Results
until You are familiar with Using Your Calculator.
One could also Use Your Casio fx-115 ES plus 0r fx-991 ES plus