document.write( "Question 1168681: Kira bought a desktop computer and a laptop computer. before finance charges, the laptop cost $200 less than the desktop. she paid for the computer 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 $306 how much did each computer cost before finance charges? \n" ); document.write( "
Algebra.Com's Answer #793260 by Theo(13342)\"\" \"About 
You can put this solution on YOUR website!
let x equal the price of the laptop.
\n" ); document.write( "let y = the price of the desktop.
\n" ); document.write( "since the desktop costs 200 more than the laptop, you get:
\n" ); document.write( "y = x+200
\n" ); document.write( "the laptop charges .07 interest rate and the desktop charges .09 interest rate.
\n" ); document.write( "the total interest is 306.
\n" ); document.write( "your equation is:
\n" ); document.write( ".07*x + .09*y = 306
\n" ); document.write( "since y = x+200, the equation becomes:
\n" ); document.write( ".07*x + .09*(x+200) = 306
\n" ); document.write( "simplify to get:
\n" ); document.write( ".07*x + .09*x + 18 = 306
\n" ); document.write( "subtract 18 from both sides of the equation and simplify to get:
\n" ); document.write( ".16*x = 288.
\n" ); document.write( "solve for x to get:
\n" ); document.write( "x = 288/.16 = 1800.
\n" ); document.write( "solve for y to get:
\n" ); document.write( "y = x+200 = 2000
\n" ); document.write( ".07*1800 + .09*2000 = 306
\n" ); document.write( "this confirms the solution is good.
\n" ); document.write( "the solution is that the laptop costs 1800 and the desktop costs 2000.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );