Question

An alloy is made of $30\%$ copper$,$ $45\%$ nickel and the rest of zinc$.$ Find the mass of zinc in $640gm$ of the alloy$.$

Answer 1

Step $1:$ To find the mass of zinc in $640gm$of the alloy.

It is given that percentage of copper in the alloy $=30\%$

Percentage of nickel in the alloy $=45\%$

Percentage of zinc $=100-\left(30+45\right)$

$=100-75$

$=25\%$

Step $2:$ Now find the $25\%$ of $640gm$

Mass of zinc $=\frac{25}{100}\times 640$

$=\frac{640}{4}$

$=160$ $gm$

Hence, mass of the zinc in $640gm$ is $160$$gm$