The total mass of 5 tanks and 6 boxes was 41.6 kg.
The total mass of 4 tanks and 4 boxes was 30 kg.
- What is the mass of 1 tank and 1 box?
- What is the mass of 7 boxes?
- How much less is the mass of 1 box than 1 tank?
(a)
5 tanks + 6 boxes = 41.6 --- (1)
4 tanks + 4 boxes = 30 --- (2)
(2)
÷ 4 1 tank + 1 box = 7.5 --- (3)
Mass of 1 tank and 1 box = 7.5 kg
(b)
(3) x 5
5 tanks + 5 boxes = 5 x 7.5
5 tanks + 5 boxes = 37.5 --- (4)
(1) - (4)
(5 tanks + 6 tanks) - (5 tanks + 5 tanks) = 41.6 - 37.5
5 tanks - 5 tanks + 6 boxes - 5 boxes = 4.1
1 box = 4.1
7 boxes = 4.1 x 7 = 28.7
Mass of 7 boxes = 28.7 kg
(c)
Substitute 1 box = 4.1 into (3).
1 tank + 1 box = 7.5
1 tank + 4.1 = 7.5
1 tank = 7.5 - 4.1 = 3.4
Mass of 1 tank = 3.4 kg
Mass of 1 tank less than 1 box
= 4.1 - 3.4
= 0.7 kg
Answer(s): (a) 7.5 kg; (b) 28.7 kg; (c) 0.7 kg