5 tanks and 4 pails can hold 16.9 litres of water.
1 tank and 1 pail can hold 3.6 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 7 pails hold?
- How many litres of water can 7 pails and 5 tanks?
(a)
5 tanks + 4 pails = 16.9 --- (1)
1 tank + 1 pail = 3.6 --- (2)
(2) x 4
1 tank + 1 pail = 3.6
4 tanks + 4 pails = 3.6 x 4
4 tanks + 4 pails = 14.4 --- (3)
(1) - (3)
(5 tanks + 4 pails) - (4 tanks + 4 pails) = 16.9 - 14.4
5 tanks + 4 pails - 4 tanks - 4 pails = 2.5
5 tanks - 4 tanks + 4 pails - 4 pails = 2.5
1 tank = 2.5
Volume of 1 tank = 2.5 ℓ
(b)
Substitute 1 tank = 2.5 into (2).
1 tank + 1 pail = 3.6
2.5 + 1 pail = 3.6
1 pail = 3.6 - 2.5 = 1.1
Volume of 1 pail = 1.1 ℓ
(c)
Volume of 7 pails
= 7 x 1.1
= 7.7 ℓ
(d)
Volume of 7 pails and 5 tanks
= 7 x 1.1 + 5 x 2.5
= 7.7 + 12.5
= 20.2 ℓ
Answer(s): (a) 2.5 ℓ; (b) 1.1 ℓ; (c) 7.7 ℓ; (d) 20.2 ℓ