Jose bought a desktop computer and a laptop computer.

Question

Jose bought a desktop computer and a laptop computer. Before finance charges, the laptop cost $350 more than the desktop. He paid for the computers using two different financing plans. For the desktop the interest rate was 7.5% per year, and for the laptop it was 8% per year. The total finance charges for one year were $400. How much did each computer cost before finance charges?

 

Please help, I am so confused!!

Answer 1

I'm not sure how they want you to calculate the finance charges, but if it's just simple interest then here is the answer  

 

Let D = cost of desktop

Then L = cost of laptop = D + 350  

 

The total finance charge for 1 year is given by  

 

0.075*D + 0.08*L = 400

0.075*D + 0.08*(D + 350) = 400

0.075*D + 0.08*D + 28 = 400

0.155*D = 372

D = 372/0.155 = $2400

 

So L = D + 350 = $2750  

 

Check:  .075*2400 + .08*2750 = 180 + 220 = $400