Find the value of B.
200 + 50 + B = 100 + 47 + 10 + 100

The value of B is 7.

B = 7

B = 7

Step-by-step explanation:

first 100 + 47 + 10 + 100 = 257

second 200 + 50 = 250

257 - 250 = 7

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.