7 containers and 6 pails can hold 28.6 litres of water.
1 container and 1 pail can hold 4.4 litres of water.

1. How many litres of water can 1 container hold?
2. How many litres of water can 1 pail hold?
3. How many litres of water can 7 pails hold?
4. How many litres of water can 4 pails and 7 containers?

(a)
7 containers + 6 pails = 28.6 --- (1)
1 container + 1 pail = 4.4 --- (2)

(2) x 6
1 container + 1 pail = 4.4
6 containers + 6 pails = 4.4 x 6
6 containers + 6 pails = 26.4 --- (3)

(1) - (3)
(7 containers + 6 pails) - (6 containers + 6 pails) = 28.6 - 26.4
7 containers + 6 pails - 6 containers - 6 pails = 2.2
7 containers - 6 containers + 6 pails - 6 pails = 2.2

1 container = 2.2

Volume of 1 container = 2.2 ℓ

(b)
Substitute 1 container = 2.2 into (2).
1 container + 1 pail = 4.4
2.2 + 1 pail = 4.4

1 pail = 4.4 - 2.2 = 2.2

Volume of 1 pail = 2.2 ℓ

(c)
Volume of 7 pails
= 7 x 2.2
= 15.4 ℓ

(d)
Volume of 4 pails and 7 containers
= 4 x 2.2 + 7 x 2.2
= 8.8 + 15.4
= 24.2 ℓ

Answer(s): (a) 2.2 ℓ; (b) 2.2 ℓ; (c) 15.4 ℓ; (d) 24.2 ℓ