Two identical pails X and Y contained some water. Pail X was ¹₆ filled and Pail Y was ¹₇ filled. The ratio of the total mass of Pail X and the water in it to the total mass of Pail Y and the water in it was 11 : 10. The total mass of the two pails and the water they contained was 2310 g. What is the mass of an empty pail?
Mass of Pail X and the water inside = 11 u
Mass of Pail Y and the water inside = 10 u

Total mass of the two pails and the water inside them
= 11 u + 10 u
= 21 u

21 u = 2310

1 u = 2310 ÷ 21 = 110

Mass of Pail X and the water in it more than mass of Pail Y and the water in it 
= 11 u - 10 u
= 1 u

Fraction of the water that Pail X had more than Pail Y 
= 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 pail
= 10 u - 6 u
= 4 u
= 4 x 110
= 440 g

Answer(s): 440 g