Question

A lump of gold is suspected to contain some quantity of aluminum.if the gold has a mass of 450g and is to have a relative density of 5.2, what is the mass of aluminium if the relative density of gold and aluminium are 19.3 and 2.6 respectively.

Answer 1

Let $x$ gm of aluminium is present in it.

Then,

Total volume = volume of aluminium + volume of gold

$$\frac{450}{5.2}=\frac{x}{2.6}+\frac{450-x}{19.3}$$

$$63.22=x(\frac{1}{2.6}-\frac{1}{19.3})$$

$$x=189.66\ gm$$