The total mass of 2 boxes and 3 tanks was 17.4 kg.
The total mass of 5 boxes and 5 tanks was 31.5 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 = 17.4 --- (1)
5 boxes + 5 tanks = 31.5 --- (2)
(2)
÷ 5 1 box + 1 tank = 6.3 --- (3)
Mass of 1 box and 1 tank = 6.3 kg
(b)
(3) x 2
2 boxes + 2 tanks = 2 x 6.3
2 boxes + 2 tanks = 12.6 --- (4)
(1) - (4)
(2 boxes + 3 tanks) - (2 boxes + 2 tanks) = 17.4 - 12.6
2 boxes - 2 boxes + 3 tanks - 2 tanks = 4.8
1 tank = 4.8
9 tanks = 4.8 x 9 = 43.2
Mass of 9 tanks = 43.2 kg
(c)
Substitute 1 tank = 4.8 into (3).
1 box + 1 tank = 6.3
1 box + 4.8 = 6.3
1 box = 6.3 - 4.8 = 1.5
Mass of 1 box = 1.5 kg
Mass of 1 box less than 1 tank
= 4.8 - 1.5
= 3.3 kg
Answer(s): (a) 6.3 kg; (b) 43.2 kg; (c) 3.3 kg