The total mass of 2 boxes and 3 tanks was 18.3 kg.
The total mass of 6 boxes and 6 tanks was 43.2 kg.
- What is the mass of 1 box and 1 tank?
- What is the mass of 7 tanks?
- How much less is the mass of 1 tank than 1 box?
(a)
2 boxes + 3 tanks = 18.3 --- (1)
6 boxes + 6 tanks = 43.2 --- (2)
(2)
÷ 6 1 box + 1 tank = 7.2 --- (3)
Mass of 1 box and 1 tank = 7.2 kg
(b)
(3) x 2
2 boxes + 2 tanks = 2 x 7.2
2 boxes + 2 tanks = 14.4 --- (4)
(1) - (4)
(2 boxes + 3 tanks) - (2 boxes + 2 tanks) = 18.3 - 14.4
2 boxes - 2 boxes + 3 tanks - 2 tanks = 3.9
1 tank = 3.9
7 tanks = 3.9 x 7 = 27.3
Mass of 7 tanks = 27.3 kg
(c)
Substitute 1 tank = 3.9 into (3).
1 box + 1 tank = 7.2
1 box + 3.9 = 7.2
1 box = 7.2 - 3.9 = 3.3
Mass of 1 box = 3.3 kg
Mass of 1 box less than 1 tank
= 3.9 - 3.3
= 0.6 kg
Answer(s): (a) 7.2 kg; (b) 27.3 kg; (c) 0.6 kg