Question

Last year, Amy had $20000 to invest. She invested some of it in an account that paid 8% simple interest per year, and she invested the rest in an account that paid 9% simple interest per year. After one year, she received a total of $1690 in interest. How much did she invest in each account?

Answer 1

Answer:

Amount invested at 8% rate of interest = $11000

Amount invested at 9% rate of interest = $9000

Step-by-step explanation:

Let Amy invested amount in a account with 8% simple interest = $a

Then the interest gained after one year = $\frac{\text{Principal amount}\times \text{Rate of interest}\times \text{Time}}{100}$

                                                                  = $\frac{a\times 8\times 1}{100}$

                                                                  = 0.08a

Remaining amount for the investment = $(20000 - a)

Interest earned after one year with rate of interest 9%

= $\frac{(20000-a)\times 9\times 1}{100}$

= $(1800 - 0.09a)

Total interest earned after 1 year = $1690

0.08a + (1800 - 0.09a) = 1690

1800 - 0.01a = 1690

0.01a = 110

a = $11000

Amount invested at 8% rate of interest = $11000

Amount invested at 9% rate of interest = $(20000 - 11000) = $9000