Show me the steps to solve An excavation contractor deposits $$200,000$ quarterly into a fund paying an interest

rate of $8\%$ per year compounded semiannually, with inter$-$period interest accrued for

a period of $4$ years. At the end of the fourth year, they want to purchase a fleet of trucks

for $$5,000,000.$ The contractor intends to make an immediate cash payment equal to

the amount accumulated and to pay for the rest by equal month$-$end payments. Their

financing agreement with the truck dealer is that payments should be completed in

$15$ months and that the interest rate should be $15\%$ per year compounded monthly.

Calculate the monthly payments for the purchase.