If $3+x=5$ and $-3+y=5$, then $x+y$ equals
(A) 4
(B) 16
(C) 6
(D) 12
(E) 10
Since $3+x=5$, then $x=2$.

Since $-3+y=5$, then $y=8$.

Thus, $x+y=10$.

Alternatively, we could have added the original two equations to obtain $(3+x)+(-3+y)=5+5$ which simplifies to $x+y=10$.

ANSWER: (E)