How much money should a couple deposit at the end of each month in an investment plan

Question:

How much money should a couple deposit at the end of each month in an investment plan that pays 7.5%, compounded monthly, so they will have $800,000 in 30 years?
(a) State whether the problem relates to an ordinary or an due, and then
(b) Solve the problem.
Annuity
An annuity is a series of equal payment made at equal intervals during a period of time. In other words annuity is a contract between insurer and insurance company in which insurer make a lump-sum payment or a series of payment and, in return,...