The total mass of 4 boxes and 5 tanks was 34.8 kg.
The total mass of 6 boxes and 6 tanks was 45 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)
4 boxes + 5 tanks = 34.8 --- (1)
6 boxes + 6 tanks = 45 --- (2)
(2)
÷ 6 1 box + 1 tank = 7.5 --- (3)
Mass of 1 box and 1 tank = 7.5 kg
(b)
(3) x 4
4 boxes + 4 tanks = 4 x 7.5
4 boxes + 4 tanks = 30 --- (4)
(1) - (4)
(4 boxes + 5 tanks) - (4 boxes + 4 tanks) = 34.8 - 30
4 boxes - 4 boxes + 5 tanks - 4 tanks = 4.8
1 tank = 4.8
7 tanks = 4.8 x 7 = 33.6
Mass of 7 tanks = 33.6 kg
(c)
Substitute 1 tank = 4.8 into (3).
1 box + 1 tank = 7.5
1 box + 4.8 = 7.5
1 box = 7.5 - 4.8 = 2.7
Mass of 1 box = 2.7 kg
Mass of 1 box less than 1 tank
= 4.8 - 2.7
= 2.1 kg
Answer(s): (a) 7.5 kg; (b) 33.6 kg; (c) 2.1 kg