When a metal is burnt its mass is increased by 24%. The equivalent mass of the metal will be

Equivalent weight of O₂​ (oxide) ion is: =8geq−1

One equivalent of the metal reacts with one equivalent of oxygen to form metal oxide.

Let M be the equivalent weight of the metal.

Therefore M grams of the metal will react with 8g  of oxygen. 

The corresponding metal oxide will have mass 8 gram more than mass of metal M. 

This 8 gram is 24% of M.

Or we can say that $\mathrm{M}\times \frac{24}{100}=8\mathrm{gram}$

So, M=$100\times \frac{8}{24}=33.33\mathrm{g}$