Two identical tanks G and H contained some water. Tank G was ¹₆ filled and Tank H was ¹₇ filled. The ratio of the total mass of Tank G and the water in it to the total mass of Tank H and the water in it was 9 : 8. The total mass of the two tanks and the water they contained was 2550 g. What is the mass of an empty tank?
Mass of Tank G and the water inside = 9 u
Mass of Tank H and the water inside = 8 u

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

17 u = 2550

1 u = 2550 ÷ 17 = 150

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

Fraction of the water that Tank G had more than Tank H 
= 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 tank
= 8 u - 6 u
= 2 u
= 2 x 150
= 300 g

Answer(s): 300 g