waecmaths question:
A rectangular board has length 15cm and width xcm. If its sides are doubled, find its new area.
Option A:
60x cm2
Option B:
45x cm2
Option C:
30x cm2
Option D:
15x cm2
waecmaths solution:
$\begin{align} & Old\text{ }length\text{ }=15cm \\ & old\text{ }width\text{ }=xcm \\ & new\text{ }length=2\times 15cm=30cm \\ & new\text{ }width=2xcm \\ & New\text{ }area=new\text{ }length\times new\text{ }width=30cm\times 2xcm \\ & New\text{ }area=60c{{m}^{2}} \\\end{align}$
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