Question 1003684
Very common application for simple two-variable linear system.


Assign variables.
x, how many three-bedroom homes
y, how many four-bedroom homes


Form equations.
{{{system(x/y=2,25000x+35000y=6800000)}}}


If you can understand that, then simply solving the system should be no trouble.


Just watch for simplification mistakes in the money equation.
{{{(25000x+35000y)/(5*1000)=6800000/(5*1000)}}}


{{{5x+7y=1360}}}
for the equivalent system
{{{system(x=2y,5x+7y=1360)}}}



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The simpler equation shown first is from, <i>...built twice as many three-bedroom homes as four-bedroom homes in a new development.</i>.  This means that x is two times y, or the ratio of x and y is 2.