The total mass of 3 boxes and 4 tanks was 18.9 kg.
The total mass of 6 boxes and 6 tanks was 31.2 kg.
- What is the mass of 1 box and 1 tank?
- What is the mass of 5 tanks?
- How much less is the mass of 1 tank than 1 box?
(a)
3 boxes + 4 tanks = 18.9 --- (1)
6 boxes + 6 tanks = 31.2 --- (2)
(2)
÷ 6 1 box + 1 tank = 5.2 --- (3)
Mass of 1 box and 1 tank = 5.2 kg
(b)
(3) x 3
3 boxes + 3 tanks = 3 x 5.2
3 boxes + 3 tanks = 15.6 --- (4)
(1) - (4)
(3 boxes + 4 tanks) - (3 boxes + 3 tanks) = 18.9 - 15.6
3 boxes - 3 boxes + 4 tanks - 3 tanks = 3.3
1 tank = 3.3
5 tanks = 3.3 x 5 = 16.5
Mass of 5 tanks = 16.5 kg
(c)
Substitute 1 tank = 3.3 into (3).
1 box + 1 tank = 5.2
1 box + 3.3 = 5.2
1 box = 5.2 - 3.3 = 1.9
Mass of 1 box = 1.9 kg
Mass of 1 box less than 1 tank
= 3.3 - 1.9
= 1.4 kg
Answer(s): (a) 5.2 kg; (b) 16.5 kg; (c) 1.4 kg