How much did each computer cost before finance charges?

Question

Donna bought a desktop computer and a laptop computer. Before the finance charges , the laptop cost $400 less than the desktop. She 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 $371. How much did each computer cost before finance charges

Answer 1

This type of problem recurs over and over in these questions. the idea is to express the words in terms of equations. Here is a simple approach

 

D = cost of desktom

L = cost of Laptop

 

D - 400 = L

.075D + .08L =  371

 

Using the first equation restate the second in terms of D

.075D + .08(D - 400) = 371

 

Solve for D and substitute in the first equation to find L.