i would hope these formulae are in your textbook.

Notation varies by country and teacher, the formulae i was taught are:

Definitions

i = interest rate (compounded once per period)

n = number of periods

S = total payment per period

FV = future value

d = rate of discount

formulae

Answer

subbing your numbers in (i assume R was the annual payment):

Now, for the interest earned. The final value must be equal to the Cash invested plus interest., so

13475.82 = (cash invested) + (interest paid)

You know that the cash invested is 1200*8, so:

You try the other one.

A more detailed overview of annuity formulae is here if required:

http://www.mathhelpforum.com/math-he...gfan+annuities