MHB How Much Did Each Computer Cost Before Finance Charges?

AI Thread Summary
Jim purchased a desktop computer for $1,750 and a laptop for $1,900 before finance charges. The laptop's price was $150 more than the desktop's. He financed the desktop at a 7% interest rate and the laptop at 5.5%. The total finance charges for one year amounted to $227. The calculations confirmed the costs of both computers based on the given equations.
jesspowers526
Messages
1
Reaction score
0
Jim bought a desktop computer and a laptop computer. Before finance charges, the laptop cost \$150 more 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 \$227.

How much did each computer cost before finance charges?
 
Last edited by a moderator:
Mathematics news on Phys.org
Hello, and welcome to MHB! (Wave)

I re-titled your thread so that the title reflects the question being asked. So, let's walk through this problem.

jesspowers526 said:
Jim bought a desktop computer and a laptop computer.

Let's let \(D\) be the cost of the desktop computer and \(L\) be the cost of the laptop computer. These costs will be in dollars.

jesspowers526 said:
Before finance charges, the laptop cost \$150 more than the desktop.

From this, we may write:

$$L=D+150$$

jesspowers526 said:
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.

So, the finance charge for the desktop is \(0.07D\) and the finance charge for the laptop is \(0.055L\).

jesspowers526 said:
The total finance charges for one year were \$227.

This allows us to write:

$$0.07D+0.055L=227$$

I would first multiply this equation by 1000 to get rid of the decimals:

$$70D+55L=227000$$

Now divide by 5:

$$14D+11L=45400$$

jesspowers526 said:
How much did each computer cost before finance charges?

We have two unknowns, which are what we're being asked to find, and two equations, so we may determine a unique solution. I would use the first equation to substitute for \(L\) into the second equation, giving us an equation in \(D\) alone, which we can then solve:

$$14D+11(D+150)=45400$$

Distribute:

$$14D+11D+1650=45400$$

Combine like terms:

$$25D=43750$$

Divide by 25:

$$D=1750$$

Now, we may use the first equation to find \(L\):

$$L=D+150=1750+150=1900$$

Thus, we have determined the cost of the desktop computer is \$1750 and the cost of the laptop computer is \$1900. Does all of that make sense?
 
Suppose ,instead of the usual x,y coordinate system with an I basis vector along the x -axis and a corresponding j basis vector along the y-axis we instead have a different pair of basis vectors ,call them e and f along their respective axes. I have seen that this is an important subject in maths My question is what physical applications does such a model apply to? I am asking here because I have devoted quite a lot of time in the past to understanding convectors and the dual...
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Back
Top