Question

The ratio of zinc and copper in an alloy is $7:9$.If the weight of copper in an alloy is $11.7kg$, find the

Total weight of alloy, weight of zinc in an alloy.

Answer 1

Let the weight of zinc and copper in an alloy is $7x$ and $9x$ respectively,

But, it is given that weight of copper is $11.7kg$.

$$\begin{gathered} 9x=11.7 \\ \Rightarrow x=\frac{11.7}{9} \\ \Rightarrow x=\frac{117}{90}=1.3kg \end{gathered}$$

$$\begin{gathered} Weightofzinc=7x \\ =7\times 1.3kg \\ =9.1kg \end{gathered}$$

Now,

$$\begin{gathered} Weightofalloy=weightofcopper+weightofzinc \\ =(11.7+9.1)Kg \\ =20.8Kg \end{gathered}$$

Therefore, weight of an alloy is $20.8kg$ and weight of zinc is $9.1kg$