Sam gets deposits a total of $3500 every three months to the bank which earns a 6.5% p/a. After five years how much will he have in his account?

Ren wants to buy a new car that costs $26255, so, he would deposit money into his savings account with an interest rate of 3.9% p/a compounded every 4 months, this has been going on for two years now. Determine Ren’s regular payment to the bank?

For Sam:

Use
F=R((1+i)^n-1)/i
F=future value
R=payment per period, $3500
i=interest, 0.065/4=0.01625
n=number of periods, 5*4=20
F=$81936 approx.

For Ren
Use the same formula for Sam, except
F=26255, i=0.013, n=2*3=6,
Find R. I get approx. $4236.