7 pails and 6 containers can hold 56.3 litres of water.
1 pail and 1 container can hold 8.4 litres of water.

1. How many litres of water can 1 pail hold?
2. How many litres of water can 1 container hold?
3. How many litres of water can 8 containers hold?
4. How many litres of water can 3 containers and 7 pails?

(a)
7 pails + 6 containers = 56.3 --- (1)
1 pail + 1 container = 8.4 --- (2)

(2) x 6
1 pail + 1 container = 8.4
6 pails + 6 containers = 8.4 x 6
6 pails + 6 containers = 50.4 --- (3)

(1) - (3)
(7 pails + 6 containers) - (6 pails + 6 containers) = 56.3 - 50.4
7 pails + 6 containers - 6 pails - 6 containers = 5.9
7 pails - 6 pails + 6 containers - 6 containers = 5.9

1 pail = 5.9

Volume of 1 pail = 5.9 ℓ

(b)
Substitute 1 pail = 5.9 into (2).
1 pail + 1 container = 8.4
5.9 + 1 container = 8.4

1 container = 8.4 - 5.9 = 2.5

Volume of 1 container = 2.5 ℓ

(c)
Volume of 8 containers
= 8 x 2.5
= 20 ℓ

(d)
Volume of 3 containers and 7 pails
= 3 x 2.5 + 7 x 5.9
= 7.5 + 41.3
= 48.8 ℓ

Answer(s): (a) 5.9 ℓ; (b) 2.5 ℓ; (c) 20 ℓ; (d) 48.8 ℓ