The total mass of 2 boxes and 3 tanks was 13.9 kg.
The total mass of 4 boxes and 4 tanks was 21.6 kg.
- What is the mass of 1 box and 1 tank?
- What is the mass of 9 tanks?
- How much less is the mass of 1 tank than 1 box?
(a)
2 boxes + 3 tanks = 13.9 --- (1)
4 boxes + 4 tanks = 21.6 --- (2)
(2)
÷ 4 1 box + 1 tank = 5.4 --- (3)
Mass of 1 box and 1 tank = 5.4 kg
(b)
(3) x 2
2 boxes + 2 tanks = 2 x 5.4
2 boxes + 2 tanks = 10.8 --- (4)
(1) - (4)
(2 boxes + 3 tanks) - (2 boxes + 2 tanks) = 13.9 - 10.8
2 boxes - 2 boxes + 3 tanks - 2 tanks = 3.1
1 tank = 3.1
9 tanks = 3.1 x 9 = 27.9
Mass of 9 tanks = 27.9 kg
(c)
Substitute 1 tank = 3.1 into (3).
1 box + 1 tank = 5.4
1 box + 3.1 = 5.4
1 box = 5.4 - 3.1 = 2.3
Mass of 1 box = 2.3 kg
Mass of 1 box less than 1 tank
= 3.1 - 2.3
= 0.8 kg
Answer(s): (a) 5.4 kg; (b) 27.9 kg; (c) 0.8 kg