Question

Six years ago Teboho invested R13125,00 at a yearly simple interest rate. Two years ago he withdrew the total accumulated sum of R17850,00. The yearly simple interest rate, i, at which Teboho invested the R13125,00 six years ago, rounded to one decimal place, is

Answer 1

Given :

Principal amount = 13125,00 Rs.

Future amount = 17850,00 Rs.

To Find :

simple interest rate at which Teboho invested the Rs. 13125,00

Solution :

Interest = Future amount - principal amount

             = 17850,00 - 13125,00

             = 4725,00

Time = Invested 6 yrs ago and withdrew the sum 2 yrs. ago

         = 4 years.

$\text{Rate of interest}=[\frac{Interest\times 100}{Principal\times Time}]%$ %

                        $=[\frac{472500\times 100}{1312500\times 4}]%$ %

                        = $\frac{472500}{52500}$ %

                        = 9%

Teboho invested the amount at the rate of interest 9%.