Two identical containers B and C contained some water. Container B was ¹₆ filled and Container C was ¹₇ filled. The ratio of the total mass of Container B and the water in it to the total mass of Container C and the water in it was 9 : 8. The total mass of the two containers and the water they contained was 3230 g. What is the mass of an empty container?
Mass of Container B and the water inside = 9 u
Mass of Container C and the water inside = 8 u

Total mass of the two containers and the water inside them
= 9 u + 8 u
= 17 u

17 u = 3230

1 u = 3230 ÷ 17 = 190

Mass of Container B and the water in it more than mass of Container C and the water in it 
= 9 u - 8 u
= 1 u

Fraction of the water that Container B had more than Container C 
= ¹₆ - ¹₇
= ⁷₄₂ - ⁶₄₂
= ¹₄₂ 

¹₄₂ of the water capacity → 1 u
⁶₄₂ of the water capacity → 6 x 1 u = 6 u

Mass of an empty container
= 8 u - 6 u
= 2 u
= 2 x 190
= 380 g

Answer(s): 380 g