The total mass of 3 boxes and 4 tanks was 26.6 kg.
The total mass of 4 boxes and 4 tanks was 29.2 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 = 26.6 --- (1)
4 boxes + 4 tanks = 29.2 --- (2)
(2)
÷ 4 1 box + 1 tank = 7.3 --- (3)
Mass of 1 box and 1 tank = 7.3 kg
(b)
(3) x 3
3 boxes + 3 tanks = 3 x 7.3
3 boxes + 3 tanks = 21.9 --- (4)
(1) - (4)
(3 boxes + 4 tanks) - (3 boxes + 3 tanks) = 26.6 - 21.9
3 boxes - 3 boxes + 4 tanks - 3 tanks = 4.7
1 tank = 4.7
7 tanks = 4.7 x 7 = 32.9
Mass of 7 tanks = 32.9 kg
(c)
Substitute 1 tank = 4.7 into (3).
1 box + 1 tank = 7.3
1 box + 4.7 = 7.3
1 box = 7.3 - 4.7 = 2.6
Mass of 1 box = 2.6 kg
Mass of 1 box less than 1 tank
= 4.7 - 2.6
= 2.1 kg
Answer(s): (a) 7.3 kg; (b) 32.9 kg; (c) 2.1 kg