The total mass of 5 boxes and 6 tanks was 18.7 kg.
The total mass of 6 boxes and 6 tanks was 19.8 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)
5 boxes + 6 tanks = 18.7 --- (1)
6 boxes + 6 tanks = 19.8 --- (2)
(2)
÷ 6 1 box + 1 tank = 3.3 --- (3)
Mass of 1 box and 1 tank = 3.3 kg
(b)
(3) x 5
5 boxes + 5 tanks = 5 x 3.3
5 boxes + 5 tanks = 16.5 --- (4)
(1) - (4)
(5 boxes + 6 tanks) - (5 boxes + 5 tanks) = 18.7 - 16.5
5 boxes - 5 boxes + 6 tanks - 5 tanks = 2.2
1 tank = 2.2
7 tanks = 2.2 x 7 = 15.4
Mass of 7 tanks = 15.4 kg
(c)
Substitute 1 tank = 2.2 into (3).
1 box + 1 tank = 3.3
1 box + 2.2 = 3.3
1 box = 3.3 - 2.2 = 1.1
Mass of 1 box = 1.1 kg
Mass of 1 box less than 1 tank
= 2.2 - 1.1
= 1.1 kg
Answer(s): (a) 3.3 kg; (b) 15.4 kg; (c) 1.1 kg