Question

Tamara invests $8000 in two different accounts. The first account has a simple interest rate of 3% and the second account has a simple interest rate of 2%. How much did she invest in each account if the interest earned in them is the same at the end of one year?

Answer 1

Let Tamara invests amount $X$ in 3% account. She invests $8000-X$ in 2% account.

The interest after t years is given by

$I=Prt$. After 1 year the two interests are equal, that is

$X(\frac{3}{100}) (1)=(8000-X)(\frac{2}{100}) (1)\\ 3X=2(8000-X)\\ 5X=16000\\ X=3200$

Thus, Tamara has to invest $\ 3200$ in 3% account and $\ 8000-\ 3200=\ 4800$ in 2% account.