Use spreadsheet functions to solve the following:

Manuel and Chad are careful planners and want to send their child to university. To pay for this they will contribute equal monthly payments to an account bearing interest at an annual rate of 4.2%, compounded monthly. They will make these payments for 15 years. Five years after their last contribution, they will begin the first of 60 monthly withdrawals of $2,970 to pay the university's installment bills. How large must their monthly contributions be?