Two identical pails E and F contained some water. Pail E was ¹₃ filled and Pail F was ¹₄ filled. The ratio of the total mass of Pail E and the water in it to the total mass of Pail F and the water in it was 8 : 7. The total mass of the two pails and the water they contained was 1650 g. What is the mass of an empty pail?
Mass of Pail E and the water inside = 8 u
Mass of Pail F and the water inside = 7 u

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

15 u = 1650

1 u = 1650 ÷ 15 = 110

Mass of Pail E and the water in it more than mass of Pail F and the water in it 
= 8 u - 7 u
= 1 u

Fraction of the water that Pail E had more than Pail F 
= ¹₃ - ¹₄
= ⁴₁₂ - ³₁₂
= ¹₁₂ 

¹₁₂ of the water capacity → 1 u
³₁₂ of the water capacity → 3 x 1 u = 3 u

Mass of an empty pail
= 7 u - 3 u
= 4 u
= 4 x 110
= 440 g

Answer(s): 440 g