Question

if 15 litre milk is used making tea and 25 ml is used for making 1 cup of tea

Answer 1

Assuming that one cup of tea is 150 ml then your answer would be: 1000 ml / 150 ml = 6.66 cups of tea

However, things get interesting when you realise that you need to add some quantity of water to the milk when it is boiling. Personally I don't but my mother and a whole lot of of people seem to enjoy doing this.

So, I assume that 1 litre of milk should produce something like 10 or 11 cups of tea that are 150 ml in size.

Answer 2

600 cups of tea can be made