The reaction, 3MnO2(s) + 4Al(s) → 3Mn(ℓ) + 2Al2O5(s) + Heat is
an example of:
In the given reaction,
3MnO2(s) + 4Al(s) → 3Mn(ℓ) + 2Al2O5(s) + Heat
Aluminum being more reactive displaces the manganese metal and forms a new compound. Hence it is a displacement reaction.
The heat is also released along with the formation of products, hence it is an exothermic reaction.