Question 1070330
x, the girl
y, her brother


{{{system(x+y=26,cross(x-3=3(y-3)),x-3=4(y-3))}}}


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{{{26-y-3=4y-12}}}------Mistake now corrected
{{{23-y=4y-12}}}
{{{23+12=5y}}}
{{{5y=35}}}



{{{highlight(cross(y=8))}}}
{{{highlight(y=7)}}}