As in Exercise 10.2, four students order noodles at a certain local restaurant. Their orders are placed independently. Each student is known to prefer Japanese pan noodles 40% of the time. How many of them do we expect to order Japanese pan noodles?
Let A1, A2, A3, A4 be the events that (respectively) the first, second, third, or fourth person orders Japanese pan noodles. Let X1, X2, X3, X4 be indicator random variables for (respectively) A1, A2, A3, A4. Justify your answer using the values of the E(Xj)'s.