d = amount of drama club students.
y = amount of yearbook students
we know their total is 94, thus d + y = 94.
but we also know that whatever "y" is, "d" is 10 more than that, d = y + 10.
[tex]\bf \begin{cases}
d+y=94\\
\boxed{d}=y+10\\
--------\\
\boxed{y+10}+y=94
\end{cases}
\\\\\\
2y=84\implies y=\cfrac{84}{2}\implies y=42[/tex]
how many are there in the drama club? well, d = y + 10.
