Two identical pails H and J contained some water. Pail H was ¹₄ filled and Pail J was ¹₅ filled. The ratio of the total mass of Pail H and the water in it to the total mass of Pail J and the water in it was 9 : 8. The total mass of the two pails and the water they contained was 3910 g. What is the mass of an empty pail?
Mass of Pail H and the water inside = 9 u
Mass of Pail J and the water inside = 8 u

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

17 u = 3910

1 u = 3910 ÷ 17 = 230

Mass of Pail H and the water in it more than mass of Pail J and the water in it 
= 9 u - 8 u
= 1 u

Fraction of the water that Pail H had more than Pail J 
= 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 pail
= 8 u - 4 u
= 4 u
= 4 x 230
= 920 g

Answer(s): 920 g