WAEC Mathematics 2016 Paper

Concept:Factor out the common $s$ from the terms on the right side, then isolate $s$ by multiplying and dividing appropriately.Explanation:Given relation: $P = s + \frac{sm^2}{nr}$.Take $s$ common from both terms on the right: $P = s\left(1 + \frac{m^2}{nr}\right)$.Combine the terms inside the bracket as a single fraction: $1 + \frac{m^2}{nr} = \frac{nr + m^2}{nr}$.So, $P = s\left(\frac{nr + m^2}{nr}\right)$.Multiply both sides by $nr$: $Pnr = s(nr + m^2)$.Divide both sides by $(nr + m^2)$ to get: $s = \frac{Pnr}{nr + m^2}$.Here $Pnr$ is the same as $nrp$, so $s = \frac{nrp}{nr + m^2}$.Answer:Option D: $s = \frac{nrp}{nr + m^2}$.