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

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

Decrease in the volume of water in Container V
= 1 interval of Container V
= 50 mℓ

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

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

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

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

Total decrease in volume of water in Containers V and W
= 50 + 80
= 130 mℓ

Volume of water in Container X in the end
= 400 + 130
= 530 mℓ

Answer(s): 530 mℓ