Question 1164367
y, Sam
x, Betty
{{{system(0.275y=0.5x,y-x=90)}}}


{{{y=x+90}}}
--
{{{275y=500x}}}
{{{11y=20x}}}
substitute,{{{11(x+90)=20x}}}
{{{11x+990=20x}}}
{{{9x=990}}}
{{{highlight(x=110)}}}
{{{and}}}
{{{highlight(y=200)}}}