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

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

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

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

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

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

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

Total decrease in volume of water in Containers A and B
= 150 + 80
= 230 mℓ

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

Answer(s): 630 mℓ