You are buying a new $800$ television, using a financial plan with a compound $2\%$ monthly

interest. You have to provide a down payment of $20\%$ of the value. You are given several

alternative to pay the remainder. Please determine the values to pay in each of the following:

a$)$ A single payment within two months

b$)$ Two equal payments in one and three months, respectively

c$)$ A $200$ payment in a month, another payment in three months and a last payment of double

the second one in six months.