Question

If the compound ratio of $7:5$ and $8:x$ is $84:60$. Find $x$.

Answer 1

We have,

Compound ratio of $7:5$ and $8:x=84:60$

$\begin{array}{cc}& \frac{7}{5}\times \frac{8}{x}=\frac{84}{60}\\ & \Rightarrow \frac{56}{5x}=\frac{84}{60}\\ & \Rightarrow 5x\times 84=60\times 56\\ & \Rightarrow x=8\end{array}$

Hence, the value of $x$ is 8