Question

Devante invests $4000 in two different accounts. The first account paid 6 %, the second account paid 11 % in interest. At the end of the first year he had earned $320 in interest. How much was in each account?

$
at 6 %

$
at 11 %

Answer 1

y=1600

x=2400

Explanation:

x+y=4000

solve for a variable

x=4000-y

plug this into .06x+.11y=320 (the interest from account 1 + account 2 must equal 320)

.06(4000-y)+.11y=320

240-.06y+.11y=320

minus 240 both sides

-.06y+.11y=80

combine terms

.05y=80

divide by .05

y=1600

to find x you subtract 1600 from 4000 to get 2400

remember, your equation must be x+y=4000

x+1600=4000

-1600

x=2400