A vessel has 5 litres and 500 ml of milk. Find how many glasses can be filled, each of 25 ml capacity.

The quantity of milk given is 5 litres and 500 ml. 

To find how many glasses can be filled, each of 25 ml capacity, first we have to convert the quantity of milk in ml and then divide by 25.

5l and 500ml = 5000 + 500 = 5500 ml

The number of glasses of 25 ml that can be filled with milk = $\frac{5500 \mathrm{ml}}{25 \mathrm{ml}}=220 \mathrm{glasses}$.

Therefore, the number of glasses is 220.