Two identical tanks V and W contained some water. Tank V was ¹₃ filled and Tank W was ¹₄ filled. The ratio of the total mass of Tank V and the water in it to the total mass of Tank W and the water in it was 6 : 5. The total mass of the two tanks and the water they contained was 2530 g. What is the mass of an empty tank?
Mass of Tank V and the water inside = 6 u
Mass of Tank W and the water inside = 5 u

Total mass of the two tanks and the water inside them
= 6 u + 5 u
= 11 u

11 u = 2530

1 u = 2530 ÷ 11 = 230

Mass of Tank V and the water in it more than mass of Tank W and the water in it 
= 6 u - 5 u
= 1 u

Fraction of the water that Tank V had more than Tank W 
= 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 tank
= 5 u - 3 u
= 2 u
= 2 x 230
= 460 g

Answer(s): 460 g