The total mass of 2 boxes and 3 tanks was 20.3 kg.
The total mass of 5 boxes and 5 tanks was 38.5 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)
2 boxes + 3 tanks = 20.3 --- (1)
5 boxes + 5 tanks = 38.5 --- (2)
(2)
÷ 5 1 box + 1 tank = 7.7 --- (3)
Mass of 1 box and 1 tank = 7.7 kg
(b)
(3) x 2
2 boxes + 2 tanks = 2 x 7.7
2 boxes + 2 tanks = 15.4 --- (4)
(1) - (4)
(2 boxes + 3 tanks) - (2 boxes + 2 tanks) = 20.3 - 15.4
2 boxes - 2 boxes + 3 tanks - 2 tanks = 4.9
1 tank = 4.9
8 tanks = 4.9 x 8 = 39.2
Mass of 8 tanks = 39.2 kg
(c)
Substitute 1 tank = 4.9 into (3).
1 box + 1 tank = 7.7
1 box + 4.9 = 7.7
1 box = 7.7 - 4.9 = 2.8
Mass of 1 box = 2.8 kg
Mass of 1 box less than 1 tank
= 4.9 - 2.8
= 2.1 kg
Answer(s): (a) 7.7 kg; (b) 39.2 kg; (c) 2.1 kg