The total mass of 2 boxes and 3 tanks was 7.7 kg.
The total mass of 4 boxes and 4 tanks was 12 kg.
- What is the mass of 1 box and 1 tank?
- What is the mass of 5 tanks?
- How much less is the mass of 1 tank than 1 box?
(a)
2 boxes + 3 tanks = 7.7 --- (1)
4 boxes + 4 tanks = 12 --- (2)
(2)
÷ 4 1 box + 1 tank = 3 --- (3)
Mass of 1 box and 1 tank = 3 kg
(b)
(3) x 2
2 boxes + 2 tanks = 2 x 3
2 boxes + 2 tanks = 6 --- (4)
(1) - (4)
(2 boxes + 3 tanks) - (2 boxes + 2 tanks) = 7.7 - 6
2 boxes - 2 boxes + 3 tanks - 2 tanks = 1.7
1 tank = 1.7
5 tanks = 1.7 x 5 = 8.5
Mass of 5 tanks = 8.5 kg
(c)
Substitute 1 tank = 1.7 into (3).
1 box + 1 tank = 3
1 box + 1.7 = 3
1 box = 3 - 1.7 = 1.3
Mass of 1 box = 1.3 kg
Mass of 1 box less than 1 tank
= 1.7 - 1.3
= 0.4 kg
Answer(s): (a) 3 kg; (b) 8.5 kg; (c) 0.4 kg