Question 985407
What happens if the difference is exactly 10? Is it a tie then?

{{{x}}}= number picked by Eric, with {{{0<=x<=20}}}
Eric wins if {{{abs(x-7)<10}}} .
{{{abs(x-7)<10}}}--->{{{-10<x-7<10}}}--->{{{-10+7<x-7+7<10+7}}}--->{{{-3<x<17}}}
Taking into account that it has to be between 0 and 20:
{{{system(0<=x<=20,-3<x<17)}}}---->{{{highlight(0<=x<=16)}}}