The figure is not drawn to scale. Tank V measuring 51 cm by 45 cm by 20 cm contained 17.58 ℓ of water. Tank W measuring 42 cm by 25 cm by 36 cm contained 21 ℓ of water. Xavier poured some water from Tank V into Tank W without spilling and the water level of Tank W rose to 28 cm. What was the height of water level left in Tank V?
1 ℓ = 1000 cm³
21 ℓ = 21000 cm³
17.58 ℓ = 17.58 x 1000 = 17580 cm³

Height of water in Tank W at first
= 21000 ÷ 42 ÷ 25
= 20 cm

Increase in the height of water in Tank W
= 28 - 20
= 8 cm

Volume of water poured into Tank W
= 42 x 25 x 8
= 8400 cm³ 

Volume of water left in Tank V
= 17580 - 8400
= 9180 cm³ 

Height of water left in Tank V
= 9180 ÷ 51 ÷ 45
= 4 cm

Answer(s): 4 cm