1.A marketing manager of a leading firm believes that total sales for the firm next year can be modelled by using a normal distribution with a mean of $15 million and a standard deviation of $3 million. What is the probability that firm's sale will fall within $2 million of the expected level of sales? Determine the sales level that has only 15% chance of being exceeded next year.

(If Possible Calculations on how to do this on excel)