Question

An alloy contains only zinc and copper in the ratio of $7:9.$ If the weight of the alloy is $\text{8 kg}$, then find the weight of copper and zinc separately in the alloy.

Answer 1

Step 1: Calculating the weight of copper -

The ratio of zinc and copper in the alloy = $7:9.$

Total number of parts = $7+9=16$

Total weight of alloy = $\text{8 kg}$

$16$ parts of the alloy has weight of alloy = $\text{8 kg}$

$1$parts of the alloy has weight of alloy = $\frac{8}{16}=\frac{1}{2}kg$

$9$parts of the alloy has weight of alloy = $\frac{1}{2}\times 9=4.5\text{kg}$

Since $9$parts represent copper in the alloy, therefore, the weight of copper in the alloy is $\text{4.5 kg}$.

Step 2: Calculating the weight of zinc -

Weight of zinc = Weight of alloy $-$ Weight of copper

= $8-4.5$

= $\text{3.5 kg}$

Hence, the weight of copper is $\text{4.5 kg}$ and weight of zinc is $\text{3.5 kg}$ in the alloy.