Question

Last year, Heather had $20,000 to invest. She invested some of it in an account that paid 6% simple interest per year, and she invested the rest in an account that paid 8% simple interest per year. After one year, she received a total of $1440 in interest. How much did she invest in each account?

Answer 1

The money invested in the account 1 was $8,000 and in the account 2 was 12,000.

Explanation:

In this case we can formulate a system of equations that could find the amount invested in each account, this is:

Money invested in the account 1 is A

Money invested in the account 2 is B

Eq. 1:
`A+B=20,000`

Eq. 2:
`(6)/(100) *A+(8)/(100) *B=1,440`

Replacing the equation 1 in 2, this is:

`(6)/(100) *(20,000-B)+(8)/(100) *B=1,440`

`1,200-0.06B+0.08B=1,440`

`0.02B=1,440-1,200`

`B=(240)/(0.02)`

`B=12,000`

Now, we can find A:

`A=20,000-B`

`A=20,000-12,000`

`A=8,000`

The money invested in the account 1 was $8,000 and in the account 2 was 12,000.