The total mass of 3 tanks and 4 boxes was 21.9 kg.
The total mass of 6 tanks and 6 boxes was 35.4 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 = 21.9 --- (1)
6 tanks + 6 boxes = 35.4 --- (2)
(2)
÷ 6 1 tank + 1 box = 5.9 --- (3)
Mass of 1 tank and 1 box = 5.9 kg
(b)
(3) x 3
3 tanks + 3 boxes = 3 x 5.9
3 tanks + 3 boxes = 17.7 --- (4)
(1) - (4)
(3 tanks + 4 tanks) - (3 tanks + 3 tanks) = 21.9 - 17.7
3 tanks - 3 tanks + 4 boxes - 3 boxes = 4.2
1 box = 4.2
7 boxes = 4.2 x 7 = 29.4
Mass of 7 boxes = 29.4 kg
(c)
Substitute 1 box = 4.2 into (3).
1 tank + 1 box = 5.9
1 tank + 4.2 = 5.9
1 tank = 5.9 - 4.2 = 1.7
Mass of 1 tank = 1.7 kg
Mass of 1 tank less than 1 box
= 4.2 - 1.7
= 2.5 kg
Answer(s): (a) 5.9 kg; (b) 29.4 kg; (c) 2.5 kg