Question

An alloy contains 40% copper, 32% nickel and rest zinc. Find the mass of zinc in one kg of the alloy.

Answer 1

$$\begin{gathered} \mathrm{Mass}\mathrm{of}\mathrm{the}\mathrm{alloy}=1\mathrm{kg} \\ \mathrm{Percentage}\mathrm{of}\mathrm{copper}=40\% \\ \mathrm{Percentage}\mathrm{of}\mathrm{nickel}=32\% \\ \mathrm{Percentage}\mathrm{of}\mathrm{zinc}=\left\{100-\left(40+32\right)\right\}\% \end{gathered}$$
$=28\%$
$\therefore \mathrm{Mass}\mathrm{of}\mathrm{zinc}\mathrm{in}1\mathrm{kg}\mathrm{of}\mathrm{alloy}=\left(\frac{28}{100}\times 1\right)\mathrm{kg}$
$=0.28\mathrm{kg}=0.28\times 1000\mathrm{g}=280\mathrm{g}$