In a typical month, an insurance agent presents lifeinsurance plans to40 potential customers. Historically,one in four such customers chooses to buy life insurance from this agent. Based on the relevant binomialdistribution, answer the following questions aboutX,the number of customers who will buy life insurancefrom this agent in the coming month:

a. What is the probability thatX is at least20?

b. Determine the mean and standard deviation ofX.

c. What is the probability thatX will be within twostandard deviations of the mean?