Pierre celebrated his birthday on February 2, 2001. On that day, his age equalled the sum of the digits in the year in which he was born. In what year was Pierre born?
(A) 1987
(B) 1980
(C) 1979
(D) 1977
(E) 1971
Pierre celebrated his birthday on February 2, 2001. On that day, his age equalled the sum of the digits in the year in which he was born. In what year was Pierre born?
(A) 1987
(B) 1980
(C) 1979
(D) 1977
(E) 1971

## Solution

We consider each of the possibilities in the following table:

|  | Year | Sum of digits | Birth year given this age |
| :---: | :---: | :---: | :---: |
| (A) | 1987 | $1+9+8+7=25$ | $2001-25=1976$ |
| (B) | 1980 | $1+9+8+0=18$ | $2001-18=1983$ |
| (C) | 1979 | $1+9+7+9=26$ | $2001-26=1975$ |
| (D) | 1977 | $1+9+7+7=24$ | $2001-24=1977$ |
| (E) | 1971 | $1+9+7+1=18$ | $2001-18=1973$ |

From the chart we can see that Pierre's birth date was 1977.

ANSWER: (D)