The total mass of 4 boxes and 5 tanks was 17.8 kg.
The total mass of 6 boxes and 6 tanks was 22.8 kg.
- What is the mass of 1 box and 1 tank?
- What is the mass of 7 tanks?
- How much less is the mass of 1 tank than 1 box?
(a)
4 boxes + 5 tanks = 17.8 --- (1)
6 boxes + 6 tanks = 22.8 --- (2)
(2)
÷ 6 1 box + 1 tank = 3.8 --- (3)
Mass of 1 box and 1 tank = 3.8 kg
(b)
(3) x 4
4 boxes + 4 tanks = 4 x 3.8
4 boxes + 4 tanks = 15.2 --- (4)
(1) - (4)
(4 boxes + 5 tanks) - (4 boxes + 4 tanks) = 17.8 - 15.2
4 boxes - 4 boxes + 5 tanks - 4 tanks = 2.6
1 tank = 2.6
7 tanks = 2.6 x 7 = 18.2
Mass of 7 tanks = 18.2 kg
(c)
Substitute 1 tank = 2.6 into (3).
1 box + 1 tank = 3.8
1 box + 2.6 = 3.8
1 box = 3.8 - 2.6 = 1.2
Mass of 1 box = 1.2 kg
Mass of 1 box less than 1 tank
= 2.6 - 1.2
= 1.4 kg
Answer(s): (a) 3.8 kg; (b) 18.2 kg; (c) 1.4 kg