A shopper spends on average 45 minutes in a store with a standard deviation of 12 minutes. Assume the length of time spent shopping in a store is normally distributed. Find the probability a shopper will be in a store between 24 and 54 minutes. If there are 200 shoppers in the store, how many shoppers would you expect will stay in the store between 24 and 54?

Please show your attempt.

P(z<-a) and P(z>a) and P(-a<z<a)