What number, when doubled and then increased by 13 , equals 89 ?
(A) 51
(B) 43
(C) 28
(D) 38
(E) 76
Solution 1

If we "undo" the operations, we would get back to the original number by first subtracting 13 and then dividing by 2 , to obtain $\frac{1}{2}(89-13)=38$.

## Solution 2

Let the number be $x$. Then $2 x+13=89$ or $2 x=76$ or $x=38$.