The total mass of 4 boxes and 5 tanks was 22.4 kg.
The total mass of 5 boxes and 5 tanks was 23.5 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)
4 boxes + 5 tanks = 22.4 --- (1)
5 boxes + 5 tanks = 23.5 --- (2)
(2)
÷ 5 1 box + 1 tank = 4.7 --- (3)
Mass of 1 box and 1 tank = 4.7 kg
(b)
(3) x 4
4 boxes + 4 tanks = 4 x 4.7
4 boxes + 4 tanks = 18.8 --- (4)
(1) - (4)
(4 boxes + 5 tanks) - (4 boxes + 4 tanks) = 22.4 - 18.8
4 boxes - 4 boxes + 5 tanks - 4 tanks = 3.6
1 tank = 3.6
9 tanks = 3.6 x 9 = 32.4
Mass of 9 tanks = 32.4 kg
(c)
Substitute 1 tank = 3.6 into (3).
1 box + 1 tank = 4.7
1 box + 3.6 = 4.7
1 box = 4.7 - 3.6 = 1.1
Mass of 1 box = 1.1 kg
Mass of 1 box less than 1 tank
= 3.6 - 1.1
= 2.5 kg
Answer(s): (a) 4.7 kg; (b) 32.4 kg; (c) 2.5 kg