The total mass of 3 boxes and 4 tanks was 27.6 kg.
The total mass of 5 boxes and 5 tanks was 39 kg.
- What is the mass of 1 box and 1 tank?
- What is the mass of 8 tanks?
- How much less is the mass of 1 tank than 1 box?
(a)
3 boxes + 4 tanks = 27.6 --- (1)
5 boxes + 5 tanks = 39 --- (2)
(2)
÷ 5 1 box + 1 tank = 7.8 --- (3)
Mass of 1 box and 1 tank = 7.8 kg
(b)
(3) x 3
3 boxes + 3 tanks = 3 x 7.8
3 boxes + 3 tanks = 23.4 --- (4)
(1) - (4)
(3 boxes + 4 tanks) - (3 boxes + 3 tanks) = 27.6 - 23.4
3 boxes - 3 boxes + 4 tanks - 3 tanks = 4.2
1 tank = 4.2
8 tanks = 4.2 x 8 = 33.6
Mass of 8 tanks = 33.6 kg
(c)
Substitute 1 tank = 4.2 into (3).
1 box + 1 tank = 7.8
1 box + 4.2 = 7.8
1 box = 7.8 - 4.2 = 3.6
Mass of 1 box = 3.6 kg
Mass of 1 box less than 1 tank
= 4.2 - 3.6
= 0.6 kg
Answer(s): (a) 7.8 kg; (b) 33.6 kg; (c) 0.6 kg