math
posted by yenny .
An amount of $3000 was deposited in a bank at a rate of 2% annual interest compounded quarterly for 3yrs. The rate then increased to 3% annual interest and ws compounded quarterly for the next 3 yrs. If no money was withdrawn what was the balance at the end of this time?

$3000 at 2% for 3 years, followed by 3% for 3 years, all compounded quarterly.
The basic equation for the future value A (accumulated amount) of a principal P at r% interest per period for n periods is:
A=PR^n
where R=1+r
At the end of the three years at 2%, the amount is reinvested at 3%, so the calculated A becomes P for the second part.
First three years:
No. of periods, n = 4*3 = 12 quarters
interest per period, 1+2%/4=1.005
Principal = $3000
Amount at the end of three years:
A = PR^n = 3000*1.005^12
= 3000*1.06168
= $3185.03
For the second part,
P=$3185.03
R=1+3%/4=1.075
n=12
A=PR^n=3185.03*1.075^12=?