The total mass of 2 boxes and 3 tanks was 13 kg.
The total mass of 4 boxes and 4 tanks was 18.8 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)
2 boxes + 3 tanks = 13 --- (1)
4 boxes + 4 tanks = 18.8 --- (2)
(2)
÷ 4 1 box + 1 tank = 4.7 --- (3)
Mass of 1 box and 1 tank = 4.7 kg
(b)
(3) x 2
2 boxes + 2 tanks = 2 x 4.7
2 boxes + 2 tanks = 9.4 --- (4)
(1) - (4)
(2 boxes + 3 tanks) - (2 boxes + 2 tanks) = 13 - 9.4
2 boxes - 2 boxes + 3 tanks - 2 tanks = 3.6
1 tank = 3.6
7 tanks = 3.6 x 7 = 25.2
Mass of 7 tanks = 25.2 kg
(c)
Substitute 1 tank = 3.6 into (3).
1 box + 1 tank = 4.7
1 box + 3.6 = 4.7
1 box = 4.7 - 3.6 = 1.1
Mass of 1 box = 1.1 kg
Mass of 1 box less than 1 tank
= 3.6 - 1.1
= 2.5 kg
Answer(s): (a) 4.7 kg; (b) 25.2 kg; (c) 2.5 kg