Question 570843
why use guess n check? that will take longer
John(j) and Bill(b)
{{{j-7=2(b-7)}}}
{{{(j+7)+(b+7)=61}}}
.
{{{j=2b-7}}}
{{{((2b-7)+7)+(b+7)=61}}}
{{{(3b+7)=61}}}
{{{3b=54}}}
{{{highlight(b=18)}}}
.

{{{j=2b-7}}}
{{{j=2(18)-7)}}}
{{{j=36-7}}}
{{{highlight(j=29)}}}
.
check
{{{j-7=2(b-7)}}}
{{{29-7=2(18-7)}}}
{{{22=22}}}
correct
check
{{{(29+7)+(18+7)=61}}}
{{{(36)+(25)=61}}}
{{{61=61}}}
correct