Question

Last year, Ann had $10,000 to invest. She invested some of it in an account that paid 7% 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 $790 in interest. How much did she invest in each account

Answer 1

Amount invested at 7% = $1,000

Amount invested at 8% = $9,000

Step-by-step explanation

Let the amount invested

at 7% = X

at 8% = Y

According to given condition

X + Y = $10,000 ( Eq 1)

and

0.07X + 0.08Y = $790 ( Eq 2)

By multiplying ( Eq 1) with 0.07

0.07X + 0.07Y = $700 ( Eq 3)

By subtracting ( Eq 3) from ( Eq 2)

0.07X - 0.07X + 0.08Y - 0.07Y = $790 - $700

0.08Y - 0.07Y = $790 - $700

0.01Y = $90

Y = $90 / 0.01

Y = $9,000

X + $9,000 = $10,000

X = $10,000 - $9,000

X = $1,000

Check:

$1,000 x 7% + $9,000 x 8% = $790

$790 = $790