Question 979697
Checking the description very carefully:  A's present age is, means A=;
4 years more than B's age AFTER 6 years, means  4+B+6;
That transcribes into {{{A=4+(B+6)}}}.  This becomes one of the equations for the system.


Present age sum becomes the other equation for the system, plainly describing {{{A+B=70}}}.


Here is the system:
{{{system(A=4+(B+6),A+B=70)}}}


The steps:


{{{system(A=B+10,A+B=70)}}}


{{{(B+10)+B=70}}}
{{{2B+10=70}}}
{{{B+5=35}}}
{{{highlight(highlight(B=30))}}}------THIS IS THE VALUE FOR B.