JAMB 2013 · UTME · Q31

If the midpoint of the line $PQ$ is $(2, 3)$ and the point $P$ is $(-2, 1)$ , find the coordinates of $Q$ .

Worked solution (try it first)

The midpoint is the average of the ends, so each coordinate of $Q$ is twice the midpoint's minus $P$ 's.
$x$ : $2(2) - (-2) = 6$ .
$y$ : $2(3) - 1 = 5$ .
So $Q = (6, 5)$ , option D.