3 tanks and 2 pails can hold 17.8 litres of water.
1 tank and 1 pail can hold 7.1 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 4 pails and 3 tanks?
(a)
3 tanks + 2 pails = 17.8 --- (1)
1 tank + 1 pail = 7.1 --- (2)
(2) x 2
1 tank + 1 pail = 7.1
2 tanks + 2 pails = 7.1 x 2
2 tanks + 2 pails = 14.2 --- (3)
(1) - (3)
(3 tanks + 2 pails) - (2 tanks + 2 pails) = 17.8 - 14.2
3 tanks + 2 pails - 2 tanks - 2 pails = 3.6
3 tanks - 2 tanks + 2 pails - 2 pails = 3.6
1 tank = 3.6
Volume of 1 tank = 3.6 ℓ
(b)
Substitute 1 tank = 3.6 into (2).
1 tank + 1 pail = 7.1
3.6 + 1 pail = 7.1
1 pail = 7.1 - 3.6 = 3.5
Volume of 1 pail = 3.5 ℓ
(c)
Volume of 9 pails
= 9 x 3.5
= 31.5 ℓ
(d)
Volume of 4 pails and 3 tanks
= 4 x 3.5 + 3 x 3.6
= 14 + 10.8
= 24.8 ℓ
Answer(s): (a) 3.6 ℓ; (b) 3.5 ℓ; (c) 31.5 ℓ; (d) 24.8 ℓ