Question 133710
 The sales representative here tells you they also have two floor plans available, but they only have 38 homes available. 
Let x be floor plan 1. Let y be floor plan 2.

Then:
{{{38 = x + y }}}

 
The representative tells you that floor plan #1 sells for $175,000 and floor plan #2 sells for $200,000.  She also mentions that all the available houses combined are worth 7,2000,000.
{{{totalWorth = HousesWithFloorPlan1 + HousesWithFloorPlan2 }}}
{{{7200000 = x (175000) + y (200000) }}}  divide by 25000
{{{288 = 7x + 8 y }}}

 Use elimination to determin how many houses with each floor plan are available. 
{{{38 = x + y }}}
{{{288 = 7x + 8 y }}}

Multiple the first equation by -7
{{{38*(-7) = -7x - 7y }}} == {{{-266 = -7x - 7y }}}

Add the two equations
{{{-266 = -7x - 7y }}}
{{{288 =   7x + 8 y }}}
-------------------------
{{{ 22 = y }}}

Substitute y back into the original first equation:
{{{38 = x + y }}}
{{{ 38 = x + 22 }}}
{{{ 16 = x }}}

Now check your answer.

{{{16*(175000) + 22*(200000)}}} = 7200000 Check!