7 containers and 6 pails can hold 75.5 litres of water.
1 container and 1 pail can hold 11.4 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 8 pails hold?
4. How many litres of water can 6 pails and 7 containers?

(a)
7 containers + 6 pails = 75.5 --- (1)
1 container + 1 pail = 11.4 --- (2)

(2) x 6
1 container + 1 pail = 11.4
6 containers + 6 pails = 11.4 x 6
6 containers + 6 pails = 68.4 --- (3)

(1) - (3)
(7 containers + 6 pails) - (6 containers + 6 pails) = 75.5 - 68.4
7 containers + 6 pails - 6 containers - 6 pails = 7.1
7 containers - 6 containers + 6 pails - 6 pails = 7.1

1 container = 7.1

Volume of 1 container = 7.1 ℓ

(b)
Substitute 1 container = 7.1 into (2).
1 container + 1 pail = 11.4
7.1 + 1 pail = 11.4

1 pail = 11.4 - 7.1 = 4.3

Volume of 1 pail = 4.3 ℓ

(c)
Volume of 8 pails
= 8 x 4.3
= 34.4 ℓ

(d)
Volume of 6 pails and 7 containers
= 6 x 4.3 + 7 x 7.1
= 25.8 + 49.7
= 75.5 ℓ

Answer(s): (a) 7.1 ℓ; (b) 4.3 ℓ; (c) 34.4 ℓ; (d) 75.5 ℓ