The total mass of 2 boxes and 3 tanks was 17.2 kg.
The total mass of 4 boxes and 4 tanks was 24.8 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)
2 boxes + 3 tanks = 17.2 --- (1)
4 boxes + 4 tanks = 24.8 --- (2)
(2)
÷ 4 1 box + 1 tank = 6.2 --- (3)
Mass of 1 box and 1 tank = 6.2 kg
(b)
(3) x 2
2 boxes + 2 tanks = 2 x 6.2
2 boxes + 2 tanks = 12.4 --- (4)
(1) - (4)
(2 boxes + 3 tanks) - (2 boxes + 2 tanks) = 17.2 - 12.4
2 boxes - 2 boxes + 3 tanks - 2 tanks = 4.8
1 tank = 4.8
7 tanks = 4.8 x 7 = 33.6
Mass of 7 tanks = 33.6 kg
(c)
Substitute 1 tank = 4.8 into (3).
1 box + 1 tank = 6.2
1 box + 4.8 = 6.2
1 box = 6.2 - 4.8 = 1.4
Mass of 1 box = 1.4 kg
Mass of 1 box less than 1 tank
= 4.8 - 1.4
= 3.4 kg
Answer(s): (a) 6.2 kg; (b) 33.6 kg; (c) 3.4 kg