Need help ASAP!

Question

At Starbucks customers can choose the drinks among three sizes: Tall, Grande, Venti. Suppose of all customers, 36% chooses Tall, 26% chooses Grande, and 38% (the rest) choose Venti. On one afternoon, 11 customers came to the store. What is the probability that between 5 to 7 customers (inclusively, so between 4.5 - 7.5 I think) choose Grande size?

Also,

What is the probability that that at most 3 customers choose Tall size?

Answer 1

Use the Binomial Distribution Formula: P_x=_nC_x•P^x•(1-P)^n-x

where X is the number of successes, N is the number of trials, and P is the probability of success.

For the first part, find P₅+P₆+P₇

Keep in mind N=11 and P=0.26

For the second part, find P₀+P₁+P₂+P₃ where P=0.36