If $a+b=12, b+c=16$, and $c=7$, what is the value of $a$ ?
(A) 1
(B) 5
(C) 9
(D) 7
(E) 3
If $a+b=12, b+c=16$, and $c=7$, what is the value of $a$ ?
(A) 1
(B) 5
(C) 9
(D) 7
(E) 3

## Solution

Since $c=7$ and $b+c=16$, then $b+7=16$, or $b=9$.

Since $b=9$ and $a+b=12$, then $a+9=12$, or $a=3$.

ANSWER: (E)