Question

Susan bought a desktop computer and a laptop computer. Before finance charges, the laptop cost $300 more than the desktop. She paid for the computers using two different financing plans. For the desktop the interest rate was 9% per year, and for the laptop it was 7% per year. The total finance charges for one year were $365. How much did each computer cost before finance charges? Desktop: s xo? Laptop: se]

Answer 1

Let cost for desktop before finance charge be x.

Then cost for laptop is x+300.

Interest rate for computer is 9 % per year. So finance charge for one year Is

$Finance\;charge=amount*\frac{interest\;rate}{100}=x*\frac{9}{100}=0.09x$

Interest rate for laptop is 7 %. So finance charge for 1 year is

$Finance\;charge=(x+300)*\frac{7}{100}=0.07x+21$

Total charge is sum of these two and equal to 365.

Total charge= 0.09x+0.07x+21=365

0.16x=365-21=344

$x=\frac{344}{0.16}=2150$

Cost for desktop=2150

cost for laptop=2150+300=2450