Used Car Sales: prob. more than 3 will sell? more than 2?

A used car salesperson estimates the probabilities for the number of cars sold in a week as follows:

number sold 0 1 2 3 4 5
-----------------------------
probability .05 .20 .30 .20 .15 .10

a) What is the probability, for a given week, that more than three cars will be sold?
b) Find the expected number of cars sold in a week?
c) What is the probability that the salesperson will sell more than 2 cars in a given week?
d) For a period of 3 weeks, what is the probability that salesperson will sell at least four cars every week?

HELP - I'm lost on this one!

Re: Used Car Sales

MBAStats said:

A used car salesperson estimates the probabilities for the number of cars sold in a week as follows:

number sold 0 1 2 3 4 5
-----------------------------
probability .05 .20 .30 .20 .15 .10

a) What is the probability, for a given week, that more than three cars will be sold?

Click to expand...

Use your table and count up the probabilities greater than 3.

Add up the probabilities > than 3

MBAStats said:

b) Find the expected number of cars sold in a week

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Use the discrete probability distribution. The expected value is the mean

\(\displaystyle \L\\\sum{xP(x)}\)

MBAStats said:

c) What is the probability that the salesperson will sell more than 2 cars in a given week?

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Add up the probabilities > 2

MBAStats said:

d) For a period of 3 weeks, what is the probability that salesperson will sell at least four cars every week?

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What are the probabilities >= 4?. Add them up and cube.