The total mass of 3 tanks and 4 boxes was 20.5 kg.
The total mass of 4 tanks and 4 boxes was 22.8 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 = 20.5 --- (1)
4 tanks + 4 boxes = 22.8 --- (2)
(2)
÷ 4 1 tank + 1 box = 5.7 --- (3)
Mass of 1 tank and 1 box = 5.7 kg
(b)
(3) x 3
3 tanks + 3 boxes = 3 x 5.7
3 tanks + 3 boxes = 17.1 --- (4)
(1) - (4)
(3 tanks + 4 tanks) - (3 tanks + 3 tanks) = 20.5 - 17.1
3 tanks - 3 tanks + 4 boxes - 3 boxes = 3.4
1 box = 3.4
9 boxes = 3.4 x 9 = 30.6
Mass of 9 boxes = 30.6 kg
(c)
Substitute 1 box = 3.4 into (3).
1 tank + 1 box = 5.7
1 tank + 3.4 = 5.7
1 tank = 5.7 - 3.4 = 2.3
Mass of 1 tank = 2.3 kg
Mass of 1 tank less than 1 box
= 3.4 - 2.3
= 1.1 kg
Answer(s): (a) 5.7 kg; (b) 30.6 kg; (c) 1.1 kg