The total mass of 3 boxes and 4 tanks was 18.1 kg.
The total mass of 4 boxes and 4 tanks was 19.6 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 = 18.1 --- (1)
4 boxes + 4 tanks = 19.6 --- (2)
(2)
÷ 4 1 box + 1 tank = 4.9 --- (3)
Mass of 1 box and 1 tank = 4.9 kg
(b)
(3) x 3
3 boxes + 3 tanks = 3 x 4.9
3 boxes + 3 tanks = 14.7 --- (4)
(1) - (4)
(3 boxes + 4 tanks) - (3 boxes + 3 tanks) = 18.1 - 14.7
3 boxes - 3 boxes + 4 tanks - 3 tanks = 3.4
1 tank = 3.4
9 tanks = 3.4 x 9 = 30.6
Mass of 9 tanks = 30.6 kg
(c)
Substitute 1 tank = 3.4 into (3).
1 box + 1 tank = 4.9
1 box + 3.4 = 4.9
1 box = 4.9 - 3.4 = 1.5
Mass of 1 box = 1.5 kg
Mass of 1 box less than 1 tank
= 3.4 - 1.5
= 1.9 kg
Answer(s): (a) 4.9 kg; (b) 30.6 kg; (c) 1.9 kg