SOLUTION: Solve using a system of equations (show the two equations you used then show the solutions): A sofa and chair cost $850 as a set. If the sofa cost $100 more than twice as much as

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Solve using a system of equations (show the two equations you used then show the solutions): A sofa and chair cost $850 as a set. If the sofa cost $100 more than twice as much as      Log On


   



Question 182509: Solve using a system of equations (show the two equations you used then show the solutions):
A sofa and chair cost $850 as a set. If the sofa cost $100 more than twice as much as the chair what is the cost of each?

Answer by MathGuyJoe(20) About Me  (Show Source):
You can put this solution on YOUR website!
Let x = cost of Sofa
Let y = cost of Chair


The first statement: "A sofa and chair cost $850 as a set" gives us:
Equation 1: +x+%2B+y+=+850+


The second statement: "...the sofa cost $100 more than twice as much of the chair" gives us:
Equation 2: +x+=+100+%2B+2y+


Now, we can substitute +%28100+%2B+2y%29+ into the first equation (in place of x) to solve for the price of the Chair (y):
+x+%2B+y+=+850+ <- Equation 1
+%28100+%2B+2y%29+%2B+y+=+850+ <- substitute in for x
+100+%2B+3y+=+850+ <- group the y's
+++++++3y+=+750+ <- subtract 100 from both sides
++++++++y+=+250+ <- divide both sides by 3


So the price for the Chair is $250. Looking at equation 1, that means the price of the Sofa must be $600.


Hope this helps! ~ Joe