Question 154382
{{{80((1.5)x) + 85 ((0.8)y)=1540}}}
{{{120x + 68y =1540}}}

{{{80x + 85 y = 1225}}}
{{{80x = 1225 - 85y}}}  multiply both sides by 1.5
{{{120x = 1837.5 - 127.5y}}} substitute back into the equation above

{{{120x + 68y =1540}}}
{{{(1837.5 - 127.5y) + 68y =1540}}}
{{{-59.5y = -297.5}}}
{{{y = 5}}}

Now find x 
{{{80x + 85 y = 1225}}}
{{{80x + 85*5 = 1225}}}
{{{80x +425 = 1225}}}
{{{80x = 800}}}
{{{x = 10}}}