Question

There are three consecutive numbers whose sum is 129. Find the square of the middle one.

• A. 1849
• B. 1764
• C. 1829
• D. 1936

Answer 1

The correct option is A 1849

Let numbers be x, x + 1, x + 2
According to question,
(x) + (x + 1) + (x + 2) = 129
$\Rightarrow$ (3x+3) = 129
$\Rightarrow$ 3x = 129-3
$\Rightarrow$ 3x = 126
$\Rightarrow$ x = 42
$\Rightarrow$ x+1 = 43
$\therefore$ (x+1)${}^2$ = 43 $\times$ 43 = 1849.