The total mass of 3 tanks and 4 boxes was 22.5 kg.
The total mass of 6 tanks and 6 boxes was 38.4 kg.
- What is the mass of 1 tank and 1 box?
- What is the mass of 9 boxes?
- How much less is the mass of 1 box than 1 tank?
(a)
3 tanks + 4 boxes = 22.5 --- (1)
6 tanks + 6 boxes = 38.4 --- (2)
(2)
÷ 6 1 tank + 1 box = 6.4 --- (3)
Mass of 1 tank and 1 box = 6.4 kg
(b)
(3) x 3
3 tanks + 3 boxes = 3 x 6.4
3 tanks + 3 boxes = 19.2 --- (4)
(1) - (4)
(3 tanks + 4 tanks) - (3 tanks + 3 tanks) = 22.5 - 19.2
3 tanks - 3 tanks + 4 boxes - 3 boxes = 3.3
1 box = 3.3
9 boxes = 3.3 x 9 = 29.7
Mass of 9 boxes = 29.7 kg
(c)
Substitute 1 box = 3.3 into (3).
1 tank + 1 box = 6.4
1 tank + 3.3 = 6.4
1 tank = 6.4 - 3.3 = 3.1
Mass of 1 tank = 3.1 kg
Mass of 1 tank less than 1 box
= 3.3 - 3.1
= 0.2 kg
Answer(s): (a) 6.4 kg; (b) 29.7 kg; (c) 0.2 kg