I need help with statistics homework

(1) Trucks arrive at a loading gate according to a Poisson distribution, at the average rate of 8.4 per hour. Find:

a) Pr (more than 13 in 75 minutes)

b) Pr (at most 4 in 10 minutes)

c) Pr (exactly 17 in two and a half hours)

(2) From past experience, we expect that 2% of a company’s invoices contain errors. We take a sample of 180 invoices. What is the probability that at least 8 contain errors?

(3) Incomes in a population are normally distributed, with a population standard deviation of $9,000. 99% of the incomes are lower than $70,000. 46% of the incomes are lower than that of Mr. Burns. Please find his income.

(4) Estimating demand for white bread .A bakery has determined that the number of loaves of its white bread demanded daily has a normal distribution with mean 7,200 loaves and standard deviation 300 loaves . Based on cost consideration , the company has decided that its best strategy is to produce a sufficient number of loaves so that it will fully supply demand on 94% of all days .

A- how many loaves of bread should the company produce ?

b-Based on the production in part a, on what percentage of days will the company be left with more than 500 loaves of unsold bread ?