An education finance corporation claims that the average credit card debts carried by undergraduates are normally distributed with a mean of $3173 and a standard deviation of $1120.Express your answers in hundredths

a. What is the probability that a randomly selected undergraduate, who is a credit card holder, has a credit card debt less than $2700

b. You randomly selected 25 undergraduates who are credit card holders. What is the probability that their mean credit card balance of the sample is less than $2700?