The total mass of 3 boxes and 4 tanks was 14.3 kg.
The total mass of 5 boxes and 5 tanks was 20 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)
3 boxes + 4 tanks = 14.3 --- (1)
5 boxes + 5 tanks = 20 --- (2)
(2)
÷ 5 1 box + 1 tank = 4 --- (3)
Mass of 1 box and 1 tank = 4 kg
(b)
(3) x 3
3 boxes + 3 tanks = 3 x 4
3 boxes + 3 tanks = 12 --- (4)
(1) - (4)
(3 boxes + 4 tanks) - (3 boxes + 3 tanks) = 14.3 - 12
3 boxes - 3 boxes + 4 tanks - 3 tanks = 2.3
1 tank = 2.3
7 tanks = 2.3 x 7 = 16.1
Mass of 7 tanks = 16.1 kg
(c)
Substitute 1 tank = 2.3 into (3).
1 box + 1 tank = 4
1 box + 2.3 = 4
1 box = 4 - 2.3 = 1.7
Mass of 1 box = 1.7 kg
Mass of 1 box less than 1 tank
= 2.3 - 1.7
= 0.6 kg
Answer(s): (a) 4 kg; (b) 16.1 kg; (c) 0.6 kg