Solve the problem using a system of equations.

Question

Paul invested twice as much money in an account paying 5% interest than he did in an account paying 1% interest. If the total interest paid was $330, how much did he invest in each?

Answer 1

Hi Janae.

 

If we let x represent the amount he invested in the account paying 1% interest, then 2x is the amount of money he invested in the account paying 5% interest.

 

The total amount of interest is represented by 0.05(2x)   [Amount of money (2x) invested at 5%]  added to  0.01(x)   [Amount of money (x) invested at 1%] .

 

 

So all together we have

 

0.05(2x) + 0.01(x) = 330

 

Simplify the left side:

 

.1x + .01x = 330

 

.11x = 330

 

Divide both sides by 0.11

 

x = 3000

 

So he invested $3000 in the 1% account, and $6000 in the 5% account.

 

Check to be sure it works:   .01(3000) + .05(6000) = 30 + 300 = 330.  YES!

 

 

Final Answer:  $3000 into the 1% account.  $6000 in the 5% account.