5 containers and 4 tanks can hold 22.1 litres of water.
1 container and 1 tank can hold 4.8 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 8 tanks hold?
4. How many litres of water can 5 tanks and 5 containers?

(a)
5 containers + 4 tanks = 22.1 --- (1)
1 container + 1 tank = 4.8 --- (2)

(2) x 4
1 container + 1 tank = 4.8
4 containers + 4 tanks = 4.8 x 4
4 containers + 4 tanks = 19.2 --- (3)

(1) - (3)
(5 containers + 4 tanks) - (4 containers + 4 tanks) = 22.1 - 19.2
5 containers + 4 tanks - 4 containers - 4 tanks = 2.9
5 containers - 4 containers + 4 tanks - 4 tanks = 2.9

1 container = 2.9

Volume of 1 container = 2.9 ℓ

(b)
Substitute 1 container = 2.9 into (2).
1 container + 1 tank = 4.8
2.9 + 1 tank = 4.8

1 tank = 4.8 - 2.9 = 1.9

Volume of 1 tank = 1.9 ℓ

(c)
Volume of 8 tanks
= 8 x 1.9
= 15.2 ℓ

(d)
Volume of 5 tanks and 5 containers
= 5 x 1.9 + 5 x 2.9
= 9.5 + 14.5
= 24 ℓ

Answer(s): (a) 2.9 ℓ; (b) 1.9 ℓ; (c) 15.2 ℓ; (d) 24 ℓ