Question 15

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Jambmaths question: 

y varies directly as w2 . When y = 8, w = 2. Find y when x = 3

Option A: 

12 

Option B: 

9

Option C: 

6

Option D: 

18

Jamb Maths Solution: 

$\begin{align}  & y\propto {{w}^{2}} \\ & y=kw\text{  (}k\text{ is the constant of proportionality)} \\ & 8=k({{2}^{2}}) \\ & k=2 \\ & \text{when }w=3 \\ & y=2{{(3)}^{2}}=18 \\\end{align}$

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