Annual Interest Rate Question

[kerniggs91]

Part of $17,000 is invested at 9% annual interest, and the rest is invested at 4%. After one year, the accounts paid $930 in interest. How much was invested at the lower rate? (Give your answer correct to the nearest cent.)

 

[Denis]

Did you read "Read before posting" ?

 

[JuicyBurger]

Did you read "Read before posting" ?

I agree.... however I'll give it a shot to help you out anyways.

With interest only paid once yearly, part at 4% and part at 9%:

Let's call the amount of money invested at 9% interest $\displaystyle x$. Therefore the amount of interest made on this amount of money is $\displaystyle x*(.09)$.
This makes the amount of money invested at 4% \(\displaystyle $17,000 - x\), the rest after subtracting $\displaystyle x$ from the total.

The amount of interest paid on this chunk of money is then $\displaystyle (17,000-x)*(.04)$.

What else do we know? We know that these two values of interest paid added together equal the total interest, \(\displaystyle $930\)