Need help, how do you get different answers for end and beginning?

P53O Value of a mixed stream For each of the mixed streams of cash flows shown in the following table, determine the future value at the end of the final year if deposits are made into an account paying annual interest of 12%, assuming that no withdrawals are made during the period and that the deposits are made a. At the and of each year (i.e., the first deposit occurs 1 year from now) b. At the beginning of each year (i.e., the first deposit occurs immediately) Cash ow stream Year A B C $ 900 $30,000 $1,200 1,000 25,000 1,200 1,200 20,000 1,000 10,000 1,900 5,000 Um-h-mNIl