5 containers and 4 tanks can hold 41.3 litres of water.
1 container and 1 tank can hold 9.2 litres of water.

1. How many litres of water can 1 container hold?
2. How many litres of water can 1 tank hold?
3. How many litres of water can 4 tanks hold?
4. How many litres of water can 9 tanks and 5 containers?

(a)
5 containers + 4 tanks = 41.3 --- (1)
1 container + 1 tank = 9.2 --- (2)

(2) x 4
1 container + 1 tank = 9.2
4 containers + 4 tanks = 9.2 x 4
4 containers + 4 tanks = 36.8 --- (3)

(1) - (3)
(5 containers + 4 tanks) - (4 containers + 4 tanks) = 41.3 - 36.8
5 containers + 4 tanks - 4 containers - 4 tanks = 4.5
5 containers - 4 containers + 4 tanks - 4 tanks = 4.5

1 container = 4.5

Volume of 1 container = 4.5 ℓ

(b)
Substitute 1 container = 4.5 into (2).
1 container + 1 tank = 9.2
4.5 + 1 tank = 9.2

1 tank = 9.2 - 4.5 = 4.7

Volume of 1 tank = 4.7 ℓ

(c)
Volume of 4 tanks
= 4 x 4.7
= 18.8 ℓ

(d)
Volume of 9 tanks and 5 containers
= 9 x 4.7 + 5 x 4.5
= 42.3 + 22.5
= 64.8 ℓ

Answer(s): (a) 4.5 ℓ; (b) 4.7 ℓ; (c) 18.8 ℓ; (d) 64.8 ℓ