Question

Miguel bought a desktop computer and a laptop computer. Before finance charges, the laptop cost $450 less than the desktop. He paid for the computers using two different financing plans. For the desktop the interest rate was 7% per year, and for the laptop it was 5.5% per year. The total finance charges for one year were $279. How much did each computer cost before finance charges?

Answer 1

Answer

Find out the how much did each computer cost before finance charges .

To proof

Let us assume that the price of the desktop computer be x .

Let us assume that the price of the laptop computer be y .

As given

the laptop cost $450 less than the desktop.

than the equation is written

y = x - 450

As given

He paid for the computers using two different financing plans.

For the desktop the interest rate was 7% per year,

the laptop it was 5.5% per year.

The total finance charges for one year were $279.

7 % is written in the decimal form

$=\frac{7}{100}$

= 0.07

5.5 % is written in the decimalform

$= \frac{5.5}{100}$

=0.055

than the equation becomes

0.07x + 0.055y = 279

simplify the above

we get

70x + 55y = 279000

put y = x - 450 in the equation

we get

70x + 55 ( x - 450 ) = 279000

70x + 55x - 24750 = 279000

125x = 303750

$x = \frac{3037550}{125}$

x = $ 2430

put in the  y = x - 450

y = 2430- 450

y =$ 1980

Therefore the desktop cost $ 2430 before finance charge.

the laptop cost $ 1980 before finance charge.

Hence proved