Question 1203980
Please help me solve this question. A boy is three times as old as his sister.<pre>{{{B = 3*S}}}</pre>In 7 years he will be twice as old as his sister will be, find their present ages.<pre>
{{{B+7 = 2(S+7)}}}

{{{system(B=3*S,B+7=2*(S+7))}}}

Simplify and solve the system by substitution.

Edwin</pre>