two equations

Question

A women invested $20,000 in two accounts, one paying 7% annual interest and the other paying 8%.  Her annual interest income from these two accounts was $1550.  How much did she have at 7%?

Answer 1

a = amount in 7% account

20000 - a = amount in 8% account

 

0.07a + 0.08 (20000 - a) = 1550

7a + 8 (20000 - a) = 155000

7a + 160000 - 8a = 155000

-a = -5000

a = 5000

 

She has five thousand dollars in the 7% account, and fifteen thousand dollars in the 8% account.