Two identical containers Y and Z contained some water. Container Y was ¹₉ filled and Container Z was ¹₁₀ filled. The ratio of the total mass of Container Y and the water in it to the total mass of Container Z and the water in it was 15 : 14. The total mass of the two containers and the water they contained was 5220 g. What is the mass of an empty container?
Mass of Container Y and the water inside = 15 u
Mass of Container Z and the water inside = 14 u

Total mass of the two containers and the water inside them
= 15 u + 14 u
= 29 u

29 u = 5220

1 u = 5220 ÷ 29 = 180

Mass of Container Y and the water in it more than mass of Container Z and the water in it 
= 15 u - 14 u
= 1 u

Fraction of the water that Container Y had more than Container Z 
= ¹₉ - ¹₁₀
= ¹⁰₉₀ - ⁹₉₀
= ¹₉₀ 

¹₉₀ of the water capacity → 1 u
⁹₉₀ of the water capacity → 9 x 1 u = 9 u

Mass of an empty container
= 14 u - 9 u
= 5 u
= 5 x 180
= 900 g

Answer(s): 900 g