A company selling vegetable seeds in packets

A company selling vegetable seeds in packets of 20 estimates that the mean number of seeds that will actually grow is 18, with a standard deviation of 1.2 seeds. You buy 5 different seed packets.

a) How many bad (non-growing) seeds do you expect to get?
b) What’s the standard deviation of the number of bad seeds?
c) What assumptions did you make about the seeds?
Do you think that assumption is warranted? Explain.