Question 1045329
{{{50(x-1)=40x}}}
{{{50x-50=40x}}}
{{{50x-50+50-40x=40x+50-40x}}}
{{{50x-40x=50}}}
{{{10x=50}}}
{{{x=50/10}}}
{{{highlight(x=5)}}}
The 40 pound child is sitting {{{highlight(5)}}} feet from the center of the teeter-totter.
The 50 pound child is sitting {{{1}}} foot closer to the center, at {{{5-1=4}}} feet from the center.