Two litres of juice are poured into 6 litres of water,what fraction of the drink is juice

Answer 1

Assuming you know the volumes are additive (technically they are not) then
2 L/8 L = 1/4 is juice.
Often, but not always, the volumes are so close to be additive that any error is too small to be of concern.

Answer 2

2/8
=1/4