Hello, I don't quite understand how to resolve the following problems:

Q1. Give the value of the following expressions, develop.

a. P(4<X<13) if X~B (15; 0,8)

b. P (X>3) if X~Po (7;8)

Q2. In a shop, the quantity of a certain food product consumed each day is a random variable that follows Poisson's binomial distribution. The expectancy is 3.5 unites per day

a) what is the probability that the quantity asked is 2 units per day? Use the appropriate notation.

b) if the sop only has 6 units of this product in store in a day, what is the probability that the seller can't respond to the demand during the day?

c) what should be the average demand in a period of 6 days?

d) what is the probability that the quantity asked is more than 10 units but less than 15 units, during a period of 4 days?