Question

A total of $14,000 is invested in 3 accounts earning 3%, 4%, and 5% annual interest. The combined interest for one year is $539. If the amount invested at 5% is three times the amount at 4%, find the amount invested at 3%.

Answer 1

If the amounts are x,y,z then we have

x+y+z = 14000
.03x + .04y + .05z = 539
z = 3y

Now just solve for x

Answer 2

7200