The total mass of 3 tanks and 4 boxes was 18.5 kg.
The total mass of 5 tanks and 5 boxes was 24.5 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)
3 tanks + 4 boxes = 18.5 --- (1)
5 tanks + 5 boxes = 24.5 --- (2)
(2)
÷ 5 1 tank + 1 box = 4.9 --- (3)
Mass of 1 tank and 1 box = 4.9 kg
(b)
(3) x 3
3 tanks + 3 boxes = 3 x 4.9
3 tanks + 3 boxes = 14.7 --- (4)
(1) - (4)
(3 tanks + 4 tanks) - (3 tanks + 3 tanks) = 18.5 - 14.7
3 tanks - 3 tanks + 4 boxes - 3 boxes = 3.8
1 box = 3.8
7 boxes = 3.8 x 7 = 26.6
Mass of 7 boxes = 26.6 kg
(c)
Substitute 1 box = 3.8 into (3).
1 tank + 1 box = 4.9
1 tank + 3.8 = 4.9
1 tank = 4.9 - 3.8 = 1.1
Mass of 1 tank = 1.1 kg
Mass of 1 tank less than 1 box
= 3.8 - 1.1
= 2.7 kg
Answer(s): (a) 4.9 kg; (b) 26.6 kg; (c) 2.7 kg