## need help on 3 problems

Beginning stat student with dyscalculia (math dyslexia)1. One out of three Americans believes that the US government should take “primary responsibility” for eliminating poverty in the US. If 10 Americans are selected, find the probability that at most 3 will believe that the US government should take primary responsibility for eliminating poverty.

I think I need to do a. 1 - 2ND>VARS>poissoncdf (10,3) but not really sure.

2. Automobiles arrive at the Elkhart exit of the Indiana toll road at the rate of 2 per minute. What is the probability that at least 6 automobiles arrive during a five minute period?

Ok this one I know I have to take the 2cars per min and times it by 5 = 10
But after that not sure what to do.

3.A lawyer believes that the probability is 0.3 that she can win a discrimination suit. If she wins the case she will make 40,000, but if she loses the she gets nothing. Assume she has to spend 5000 preparing the case. What is the standard deviation for the probability distribution? The expected profit is 8500/

x p(x)
40,000 0.3
-5000 0.7

I think I have to (40,000 - 5000)^2(.03)+(-5000 -5000)^2(0.7)
But not sure what to do with the the 8500 or the 5000 she has to spend.