9 tanks and 8 pails can hold 53.6 litres of water.
1 tank and 1 pail can hold 6.3 litres of water.
- How many litres of water can 1 tank hold?
- How many litres of water can 1 pail hold?
- How many litres of water can 9 pails hold?
- How many litres of water can 8 pails and 9 tanks?
(a)
9 tanks + 8 pails = 53.6 --- (1)
1 tank + 1 pail = 6.3 --- (2)
(2) x 8
1 tank + 1 pail = 6.3
8 tanks + 8 pails = 6.3 x 8
8 tanks + 8 pails = 50.4 --- (3)
(1) - (3)
(9 tanks + 8 pails) - (8 tanks + 8 pails) = 53.6 - 50.4
9 tanks + 8 pails - 8 tanks - 8 pails = 3.2
9 tanks - 8 tanks + 8 pails - 8 pails = 3.2
1 tank = 3.2
Volume of 1 tank = 3.2 ℓ
(b)
Substitute 1 tank = 3.2 into (2).
1 tank + 1 pail = 6.3
3.2 + 1 pail = 6.3
1 pail = 6.3 - 3.2 = 3.1
Volume of 1 pail = 3.1 ℓ
(c)
Volume of 9 pails
= 9 x 3.1
= 27.9 ℓ
(d)
Volume of 8 pails and 9 tanks
= 8 x 3.1 + 9 x 3.2
= 24.8 + 28.8
= 53.6 ℓ
Answer(s): (a) 3.2 ℓ; (b) 3.1 ℓ; (c) 27.9 ℓ; (d) 53.6 ℓ