Question

Last year, Jina had 30,000 to invest. She invested some of it in an account that paid 9%simple interest per year, and she invested the rest in an account that paid 5% simple interest per year. After one year, she received a total of $1540 in interest. How much did she invest in each account?

first account :

second:

Answer 1

Amount invested in first account = $1,000

Amount invested in second account = $29,000

Explanation:

Jina had total amount of $30,000 to invest last year.

Let x be the amount that Jina invested in the first account at interest rate of 9%

Mathematically,

0.09x

she invested the remaining amount in the second account at an interest rate of 5%

Mathematically,

0.05(30,000 - x)

Jina received $1540 in interest.

0.09x + 0.05(30,000 - x) = 1540

0.09x + 1500 - 0.05x = 1540

0.04x = 1540 - 1500

0.04x = 40

x = 40/0.04

x = $1,000

Therefore, Jina invested an amount of $1,000 in the first account at interest rate of 9%

The remaining amount that she invested in the second account is

Amount invested in second account = $30,000 - $1,000

Amount invested in second account = $29,000

Therefore, Jina invested an amount of $29,000 in the second account at interest rate of 5%

Verification:

0.09x + 0.05(30,000 - x) = 1540

0.09(1000) + 0.05(30,000 - 1000) = 1540

90 + 1450 = 1540

1540 = 1540 (satisfied)