Silver Star, Inc. has a number of stores in major metropolitan shoppingcenters.

Silver Star, Inc. has a number of stores in major metropolitan shoppingcenters. The company’s sales experience indicates that daily cell phonesales in its stores follow a normal distribution with a mean of 60 and astandard deviation of 15. The marketing department conducts a number ofroutine analyses of sales data to monitor sales performance. 

a)      What proportion of store sales days will have sales between 85 and 95given that sales are following the historical experience?

b)      Find the cutoff point for the top 10% of all daily sales.