The total mass of 3 boxes and 4 tanks was 20.3 kg.
The total mass of 5 boxes and 5 tanks was 27 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 = 20.3 --- (1)
5 boxes + 5 tanks = 27 --- (2)
(2)
÷ 5 1 box + 1 tank = 5.4 --- (3)
Mass of 1 box and 1 tank = 5.4 kg
(b)
(3) x 3
3 boxes + 3 tanks = 3 x 5.4
3 boxes + 3 tanks = 16.2 --- (4)
(1) - (4)
(3 boxes + 4 tanks) - (3 boxes + 3 tanks) = 20.3 - 16.2
3 boxes - 3 boxes + 4 tanks - 3 tanks = 4.1
1 tank = 4.1
9 tanks = 4.1 x 9 = 36.9
Mass of 9 tanks = 36.9 kg
(c)
Substitute 1 tank = 4.1 into (3).
1 box + 1 tank = 5.4
1 box + 4.1 = 5.4
1 box = 5.4 - 4.1 = 1.3
Mass of 1 box = 1.3 kg
Mass of 1 box less than 1 tank
= 4.1 - 1.3
= 2.8 kg
Answer(s): (a) 5.4 kg; (b) 36.9 kg; (c) 2.8 kg