The total mass of 3 boxes and 4 tanks was 15.1 kg.
The total mass of 4 boxes and 4 tanks was 16.8 kg.
- What is the mass of 1 box and 1 tank?
- What is the mass of 9 tanks?
- How much less is the mass of 1 tank than 1 box?
(a)
3 boxes + 4 tanks = 15.1 --- (1)
4 boxes + 4 tanks = 16.8 --- (2)
(2)
÷ 4 1 box + 1 tank = 4.2 --- (3)
Mass of 1 box and 1 tank = 4.2 kg
(b)
(3) x 3
3 boxes + 3 tanks = 3 x 4.2
3 boxes + 3 tanks = 12.6 --- (4)
(1) - (4)
(3 boxes + 4 tanks) - (3 boxes + 3 tanks) = 15.1 - 12.6
3 boxes - 3 boxes + 4 tanks - 3 tanks = 2.5
1 tank = 2.5
9 tanks = 2.5 x 9 = 22.5
Mass of 9 tanks = 22.5 kg
(c)
Substitute 1 tank = 2.5 into (3).
1 box + 1 tank = 4.2
1 box + 2.5 = 4.2
1 box = 4.2 - 2.5 = 1.7
Mass of 1 box = 1.7 kg
Mass of 1 box less than 1 tank
= 2.5 - 1.7
= 0.8 kg
Answer(s): (a) 4.2 kg; (b) 22.5 kg; (c) 0.8 kg