Two identical buckets G and H contained some water. Bucket G was ¹₄ filled and Bucket H was ¹₅ filled. The ratio of the total mass of Bucket G and the water in it to the total mass of Bucket H and the water in it was 7 : 6. The total mass of the two buckets and the water they contained was 3380 g. What is the mass of an empty bucket?
Mass of Bucket G and the water inside = 7 u
Mass of Bucket H and the water inside = 6 u

Total mass of the two buckets and the water inside them
= 7 u + 6 u
= 13 u

13 u = 3380

1 u = 3380 ÷ 13 = 260

Mass of Bucket G and the water in it more than mass of Bucket H and the water in it 
= 7 u - 6 u
= 1 u

Fraction of the water that Bucket G had more than Bucket 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 bucket
= 6 u - 4 u
= 2 u
= 2 x 260
= 520 g

Answer(s): 520 g