c = Charmaine's age.
w = William's age.
"William is 3 years older than Charmaine" w = c + 3.
"3 times Charmaine's age" 3c.
"2 times William's age" 2w.
"sum of both of those is 76" 3c + 2w = 76
[tex]\bf \begin{cases}
\boxed{w}=c+3\\
3c+2w=76\\
--------\\
3c+2\left( \boxed{c+3} \right)=76
\end{cases}
\\\\\\
3c+2c+6=76\implies 5c=70\implies c=\cfrac{70}{5}\implies c=14[/tex]
how old is William? well, w = c + 3.
