Answer:
Ravi had 355ml water to begin with.
Step-by-step explanation:
Given that,
amount of water that Gwent pour in Ravi = 256 ml
amount of water that Henry pour in Ravi = 189 ml
amount of water after each have poured = 800 ml
suppose amount of water ravi had before both poured water in it = x
Equation
256 + 189 + x = 800
445 + x = 800
x = 355ml
Initially ravi had 335ml of water.