Question

An alloy contains 30% copper, 42% nickel and rest zinc. Find the mass of zinc in 1 kg of alloy.

Answer 1

$$\begin{gathered} \mathrm{Percentage}\mathrm{of}\mathrm{copper}=30\% \\ \mathrm{Percentage}\mathrm{of}\mathrm{nickel}=42\% \\ \mathrm{Percentage}\mathrm{of}\mathrm{zinc}=\left\{100-\left(30+42\right)\right\}\% \end{gathered}$$
$=28\%$

$\therefore \mathrm{Mass}\mathrm{of}\mathrm{zinc}\mathrm{in}1\mathrm{kg}\mathrm{of}\mathrm{the}\mathrm{alloy}=\left(\frac{28}{100}\times 1\right)\mathrm{kg}=0.28\mathrm{kg}=280\mathrm{g}$