Two identical containers G and H contained some water. Container G was ¹₄ filled and Container H was ¹₅ 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 8 : 7. The total mass of the two containers and the water they contained was 2700 g. What is the mass of an empty container?
Mass of Container G and the water inside = 8 u
Mass of Container H and the water inside = 7 u

Total mass of the two containers and the water inside them
= 8 u + 7 u
= 15 u

15 u = 2700

1 u = 2700 ÷ 15 = 180

Mass of Container G and the water in it more than mass of Container H and the water in it 
= 8 u - 7 u
= 1 u

Fraction of the water that Container G had more than Container H 
= ¹₄ - ¹₅
= ⁵₂₀ - ⁴₂₀
= ¹₂₀ 

¹₂₀ of the water capacity → 1 u
⁴₂₀ of the water capacity → 4 x 1 u = 4 u

Mass of an empty container
= 7 u - 4 u
= 3 u
= 3 x 180
= 540 g

Answer(s): 540 g