HELP is for my economics class

Jimmy owns an ice cream parlor. he designs a schedule for the different tasks the employees have to perform in order to prevent monotony at work. according to the schedule, if an employee makes waffle cones on a day, he serves ice creams the next day and clears the tables on the day after that. jimmy is using the approach at his ice cream parlor.

Stocks a, b, and c are similar in some respects: each has an expected return of 10% and a standard deviation of 25%. stocks a and b have returns that are independent of one another; i.e., their correlation coefficient, r, equals zero. stocks a and c have returns that are negatively correlated with one another; i.e., r is less than 0. portfolio ab is a portfolio with half of its money invested in stock a and half in stock b. portfolio ac is a portfolio with half of its money invested in stock a and half invested in stock c. which of the following statements is correct? a. portfolio ab has a standard deviation that is greater than 25%.b. portfolio ac has an expected return that is less than 10%.c. portfolio ac has a standard deviation that is less than 25%.d. portfolio ab has a standard deviation that is equal to 25%.e. portfolio ac has an expected return that is greater than 25%.

Ashop owner uses a reorder point approach to restocking a certain raw material. lead time is six days. usage of the material during lead time is normally distributed with a mean of 42 pounds and a standard deviation of four pounds. when should the raw material be reordered if the acceptable risk of a stockout is 3 percent?