PSLE
Two containers are not drawn to scale. At first, Container W was empty and one-third of Container X was filled with water. Both taps were turned on at the same time and water from both taps flowed at the same rate of 1.6 litres per minute. How much time will it take for the height of the water to be the same in both tanks? (Express your answer in min.)
1 ℓ = 1000 cm³
1.6 ℓ = 1600 cm³

Initial height of water in Container X
= ¹₃ x 48 
= 16 cm

Base area of Container W
= 50 x 10
= 500 cm²

Rise of water level in Container W in a minute
= 1600 ÷ 500
= 3.2 cm

Base area of Container X
= 50 x 20
= 1000 cm²

Rise of water level in Container X in a minute
= 1600 ÷ 1000
= 1.6 cm

Difference in the rise of water in Container W and Container X in a minute
= 3.2 - 1.6
= 1.6 cm

Time taken for the height of water to be the same
= 16 ÷ 1.6
= 10 min

Answer(s): 10 min