Two identical containers F and G contained some water. Container F was ¹₇ filled and Container G was ¹₈ filled. The ratio of the total mass of Container F and the water in it to the total mass of Container G and the water in it was 10 : 9. The total mass of the two containers and the water they contained was 2470 g. What is the mass of an empty container?
Mass of Container F and the water inside = 10 u
Mass of Container G and the water inside = 9 u

Total mass of the two containers and the water inside them
= 10 u + 9 u
= 19 u

19 u = 2470

1 u = 2470 ÷ 19 = 130

Mass of Container F and the water in it more than mass of Container G and the water in it 
= 10 u - 9 u
= 1 u

Fraction of the water that Container F had more than Container G 
= ¹₇ - ¹₈
= ⁸₅₆ - ⁷₅₆
= ¹₅₆ 

¹₅₆ of the water capacity → 1 u
⁷₅₆ of the water capacity → 7 x 1 u = 7 u

Mass of an empty container
= 9 u - 7 u
= 2 u
= 2 x 130
= 260 g

Answer(s): 260 g