waecmaths question:
if x : y = 3 : 2 and y : z = 5 : 4, find the value of x in the ratio x: y: z
Option A:
8
Option B:
10
Option C:
11
Option D:
15
waecmaths solution:
$\begin{align} & \frac{x}{y}=\frac{3}{2} \\ & x=\frac{3y}{2} \\ & \frac{y}{z}=\frac{5}{4} \\ & z=\frac{4y}{5} \\ & x:y:z=\frac{3y}{2}:y:\frac{4y}{5} \\ & \text{Multiply through by }10 \\ & 10x:10y:10z=15:10:8 \\ & \text{The value of }x=15 \\\end{align}$
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