The total mass of 5 boxes and 6 tanks was 16.9 kg.
The total mass of 4 boxes and 4 tanks was 12 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 = 16.9 --- (1)
4 boxes + 4 tanks = 12 --- (2)
(2)
÷ 4 1 box + 1 tank = 3 --- (3)
Mass of 1 box and 1 tank = 3 kg
(b)
(3) x 5
5 boxes + 5 tanks = 5 x 3
5 boxes + 5 tanks = 15 --- (4)
(1) - (4)
(5 boxes + 6 tanks) - (5 boxes + 5 tanks) = 16.9 - 15
5 boxes - 5 boxes + 6 tanks - 5 tanks = 1.9
1 tank = 1.9
7 tanks = 1.9 x 7 = 13.3
Mass of 7 tanks = 13.3 kg
(c)
Substitute 1 tank = 1.9 into (3).
1 box + 1 tank = 3
1 box + 1.9 = 3
1 box = 3 - 1.9 = 1.1
Mass of 1 box = 1.1 kg
Mass of 1 box less than 1 tank
= 1.9 - 1.1
= 0.8 kg
Answer(s): (a) 3 kg; (b) 13.3 kg; (c) 0.8 kg