WAEC 2022 · Paper 1 · Q9

Variation

$M$ varies directly as $n$ and inversely as the square of $p$ . If $M = 3$ when $n = 2$ and $p = 1$ , find $M$ in terms of $n$ and $p$ .

Worked solution (try it first)

Directly as $n$ , inversely as $p^2$ : $M = \dfrac{kn}{p^2}$ .
Put in $M = 3$ , $n = 2$ , $p = 1$ : $3 = 2k$ , so $k = \frac32$ .
So $M = \dfrac{3n}{2p^2}$ , option A.

Report a problem with this question