Math question? anyone willing to try?

Question

You invest $200. After on year, the total of the investment is $208.80. Solve the formula A=P+Prt where A is the total of the investment, P is the principal (amount invested), r is the annuall simple interest rate, and t is the time in years, for r. Find the annual simple interest rate. How much money would your investment have if you leave it in for another two years with the same interest rate? Explain your answer.

Answer 1

Part 1:
P=200 (Amount invested)
t=1 (Invested for one year)
A=208.80 (total investment after 1 year)
Solve for r ----> r = (A-P)/(Pt)
r=0.044

Part 2:
P=200
r=Answer from Part 1
t=3 years (1 year + 2 years)
Solve for A
I get $226.40

Or you could use P=208.80; t=2 years and you should have the same answer.

I get 227.20 calculating this way (not sure why they differ slightly; possibly due to rounding.

Answer 2

If you made $8.80 on a $200 investment you earned 4.4%

208.8 = 200(1+r)1; r=.044 or 4.4%

if interest is compounded annually, after 3years (another 2 years)
you would have 200(1.044)^3 = $227.57

Answer 3

5.76