A total of 60% of the customers of a fast-food chain order a hamburger,french fries,and a drink. If a random sample of 15 cash register receipts is selected,what is the probability that 10 or more will show that the above three food items were ordered?
A)1.000
B)0.186
C)0.403
D)0.000

Question

Quizplus · Accepted Answer

We can use the binomial distribution formula with n = 15 and p = 0.6 (since 60% of customers order the three items).
P(X ≥ 10) = 1 - P(X < 10)
= 1 - Σ_(i=0)^9 (15 choose i) * (0.6)^i * (0.4)^(15-i)
Using a calculator, we get P(X ≥ 10) = 0.403, which corresponds to choice C.

A Total of 60% of the Customers of a Fast-Food