8 containers and 7 tanks can hold 77.5 litres of water.
1 container and 1 tank can hold 10 litres of water.
- How many litres of water can 1 container hold?
- How many litres of water can 1 tank hold?
- How many litres of water can 4 tanks hold?
- How many litres of water can 3 tanks and 8 containers?
(a)
8 containers + 7 tanks = 77.5 --- (1)
1 container + 1 tank = 10 --- (2)
(2) x 7
1 container + 1 tank = 10
7 containers + 7 tanks = 10 x 7
7 containers + 7 tanks = 70 --- (3)
(1) - (3)
(8 containers + 7 tanks) - (7 containers + 7 tanks) = 77.5 - 70
8 containers + 7 tanks - 7 containers - 7 tanks = 7.5
8 containers - 7 containers + 7 tanks - 7 tanks = 7.5
1 container = 7.5
Volume of 1 container = 7.5 ℓ
(b)
Substitute 1 container = 7.5 into (2).
1 container + 1 tank = 10
7.5 + 1 tank = 10
1 tank = 10 - 7.5 = 2.5
Volume of 1 tank = 2.5 ℓ
(c)
Volume of 4 tanks
= 4 x 2.5
= 10 ℓ
(d)
Volume of 3 tanks and 8 containers
= 3 x 2.5 + 8 x 7.5
= 7.5 + 60
= 67.5 ℓ
Answer(s): (a) 7.5 ℓ; (b) 2.5 ℓ; (c) 10 ℓ; (d) 67.5 ℓ