Tony bought a desktop computer and a laptop computer. Before finance charges, the laptop cost
$400
less than the desktop. He paid for the computers using two different financing plans. For the desktop the interest rate was
8.5%
per year, and for the laptop it was
5%
per year. The total finance charges for one year were
$412
. How much did each computer cost before finance charges?

Question

Tony bought a desktop computer and a laptop computer. Before finance charges, the laptop cost 
$400
 less than the desktop. He paid for the computers using two different financing plans. For the desktop the interest rate was 
8.5%
 per year, and for the laptop it was 
5%
 per year. The total finance charges for one year were 
$412
 . How much did each computer cost before finance charges?

dtan5457 · Answer

Might have to give me 10 minutes for this one..

dtan5457 · Answer

Before finance charges, the laptop cost $400 less than the desktop.

desktop: x
laptop: x-400

interest on desktop: x(0.085)
interest on laptop: x-400(0.05)

total finance charges were $412

now you need to add the interests

0.085x+0.05(x-400)=412

multiply everything by 100

85x+50x-50(400)=412000

90x-20000=412000

add the 20000

90x=432000

x=4800<<cost of desktop

4800-400=4400<<cost of laptop

dtan5457 · Answer

Good?

anonymous · Answer

thanks