The total mass of 3 boxes and 4 tanks was 28.2 kg.
The total mass of 5 boxes and 5 tanks was 40 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)
3 boxes + 4 tanks = 28.2 --- (1)
5 boxes + 5 tanks = 40 --- (2)
(2)
÷ 5 1 box + 1 tank = 8 --- (3)
Mass of 1 box and 1 tank = 8 kg
(b)
(3) x 3
3 boxes + 3 tanks = 3 x 8
3 boxes + 3 tanks = 24 --- (4)
(1) - (4)
(3 boxes + 4 tanks) - (3 boxes + 3 tanks) = 28.2 - 24
3 boxes - 3 boxes + 4 tanks - 3 tanks = 4.2
1 tank = 4.2
9 tanks = 4.2 x 9 = 37.8
Mass of 9 tanks = 37.8 kg
(c)
Substitute 1 tank = 4.2 into (3).
1 box + 1 tank = 8
1 box + 4.2 = 8
1 box = 8 - 4.2 = 3.8
Mass of 1 box = 3.8 kg
Mass of 1 box less than 1 tank
= 4.2 - 3.8
= 0.4 kg
Answer(s): (a) 8 kg; (b) 37.8 kg; (c) 0.4 kg