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

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

Decrease in the volume of water in Container C
= 3 intervals of Container C
= 3 x 50
= 150 mℓ

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

Decrease in the volume of water in Container D
= 4 intervals of Container D
= 4 x 20 
= 80 mℓ

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

Volume of water in Container E at first
= 4 intervals of Container E
= 4 x 100
= 400 mℓ

Total decrease in volume of water in Containers C and D
= 150 + 80
= 230 mℓ

Volume of water in Container E in the end
= 400 + 230
= 630 mℓ

Answer(s): 630 mℓ