Question 1169905
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The given information gives us two equations:<br>
{{{70x+80y = 335}}}
{{{100x+50y = 395}}}<br>
My definite preference for solving a system of equations in this form is elimination.  Multiply one or both equations by constants so that the coefficients of one of the variables are the same in the two equations; then subtract one equation from the other to eliminate that variable.<br>
{{{350x+400y = 1675}}}
{{{800x+400y = 3160}}}
{{{450x = 1485}}}
{{{x = 1485/450 = 3.3}}}<br>
Then substitute x=3.3 in either original equation to solve for y.<br>
{{{70(3.3)+80y = 335}}}
{{{231+80y = 335}}}
{{{80y = 104}}}
{{{y = 1.3}}}<br>
ANSWERS: x = $3.30 per foot for redwood; y = $1.30 per foot for pine.<br>