Two identical containers G and H contained some water. Container G was ¹₂ filled and Container H was ¹₃ filled. The ratio of the total mass of Container G and the water in it to the total mass of Container H and the water in it was 6 : 5. The total mass of the two containers and the water they contained was 1320 g. What is the mass of an empty container?
Mass of Container G and the water inside = 6 u
Mass of Container H and the water inside = 5 u

Total mass of the two containers and the water inside them
= 6 u + 5 u
= 11 u

11 u = 1320

1 u = 1320 ÷ 11 = 120

Mass of Container G and the water in it more than mass of Container H and the water in it 
= 6 u - 5 u
= 1 u

Fraction of the water that Container G had more than Container H 
= ¹₂ - ¹₃
= ³₆ - ²₆
= ¹₆ 

¹₆ of the water capacity → 1 u
²₆ of the water capacity → 2 x 1 u = 2 u

Mass of an empty container
= 5 u - 2 u
= 3 u
= 3 x 120
= 360 g

Answer(s): 360 g