PSLE
At first, Containers D, E and F contained water as shown in Figure 1. Some water from D and E was poured into Container F without spilling. The amount of water left in Container D and E is shown in Figure 2. What would be the amount of water in Container F?
1 ℓ = 1000 mℓ

Container D 
10 intervals = 500
1 interval = 500 ÷ 10 = 50

Decrease in the volume of water in Container D
= 2 intervals of Container D
= 2 x 50
= 100 mℓ

Container E
10 intervals = 200
1 interval = 200 ÷ 10 = 20

Decrease in the volume of water in Container E
= 2 intervals of Container E
= 2 x 20 
= 40 mℓ

Container F
10 intervals = 1000
1 interval = 1000 ÷ 10 = 100

Volume of water in Container F at first
= 6 intervals of Container F
= 6 x 100
= 600 mℓ

Total decrease in volume of water in Containers D and E
= 100 + 40
= 140 mℓ

Volume of water in Container F in the end
= 600 + 140
= 740 mℓ

Answer(s): 740 mℓ