The total mass of 3 boxes and 4 tanks was 25.3 kg.
The total mass of 4 boxes and 4 tanks was 28.8 kg.
- What is the mass of 1 box and 1 tank?
- What is the mass of 6 tanks?
- How much less is the mass of 1 tank than 1 box?
(a)
3 boxes + 4 tanks = 25.3 --- (1)
4 boxes + 4 tanks = 28.8 --- (2)
(2)
÷ 4 1 box + 1 tank = 7.2 --- (3)
Mass of 1 box and 1 tank = 7.2 kg
(b)
(3) x 3
3 boxes + 3 tanks = 3 x 7.2
3 boxes + 3 tanks = 21.6 --- (4)
(1) - (4)
(3 boxes + 4 tanks) - (3 boxes + 3 tanks) = 25.3 - 21.6
3 boxes - 3 boxes + 4 tanks - 3 tanks = 3.7
1 tank = 3.7
6 tanks = 3.7 x 6 = 22.2
Mass of 6 tanks = 22.2 kg
(c)
Substitute 1 tank = 3.7 into (3).
1 box + 1 tank = 7.2
1 box + 3.7 = 7.2
1 box = 7.2 - 3.7 = 3.5
Mass of 1 box = 3.5 kg
Mass of 1 box less than 1 tank
= 3.7 - 3.5
= 0.2 kg
Answer(s): (a) 7.2 kg; (b) 22.2 kg; (c) 0.2 kg