i would hope these formulae are in your textbook.
Notation varies by country and teacher, the formulae i was taught are:
i = interest rate (compounded once per period)
n = number of periods
S = total payment per period
FV = future value
d = rate of discount
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: