Just need help in setting up this word problem

[passionflower_40]

Dorothy bought two computers, one desktop and one laptop. Before finance charges, the laptop cost $1000 less than the desktop. Dorothy paid for the computers using two different financing plans. For the desktop the interest rate was 8% per year, and for the laptop it was 7% per year. The total finance charges for one year were $492.50 . How much did the desktop computer cost before finance charges?

 

[dagr8est]

Let D = cost of desktop in dollars
Then D-1000 = cost of laptop in dollars
Then 0.08D = interest on desktop for 1 year
Then 0.07(D-1000) = interest on laptop for 1 year

total cost = (cost of desktop)+(cost of laptop)+(interest on desktop)+(interest on laptop)
492.5 = D+D-1000+0.08D+0.07(D-1000)

Solve the equation.

 

[passionflower_40]

Thank you dagrBest

I will come back with an answer and just need to know if I was going in the right direction or not and my mistake please.

 

[passionflower_40]

Let D = cost of desktop in dollars
Then D-1000 = cost of laptop in dollars
Then 0.08D = interest on desktop for 1 year
Then 0.07(D-1000) = interest on laptop for 1 year

total cost = (cost of desktop)+(cost of laptop)+(interest on desktop)+(interest on laptop)
492.5 = D+D-1000+0.08D+0.07(D-1000)

Solve the equation.

I could not figure this one out even with the formula expressed. I need to know why you stated $492.50 when it was just the interest rate for one year? I got lost on that being the total cost can you clarify that for me please.