The total mass of 2 tanks and 3 boxes was 9 kg.
The total mass of 5 tanks and 5 boxes was 17 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)
2 tanks + 3 boxes = 9 --- (1)
5 tanks + 5 boxes = 17 --- (2)
(2)
÷ 5 1 tank + 1 box = 3.4 --- (3)
Mass of 1 tank and 1 box = 3.4 kg
(b)
(3) x 2
2 tanks + 2 boxes = 2 x 3.4
2 tanks + 2 boxes = 6.8 --- (4)
(1) - (4)
(2 tanks + 3 tanks) - (2 tanks + 2 tanks) = 9 - 6.8
2 tanks - 2 tanks + 3 boxes - 2 boxes = 2.2
1 box = 2.2
7 boxes = 2.2 x 7 = 15.4
Mass of 7 boxes = 15.4 kg
(c)
Substitute 1 box = 2.2 into (3).
1 tank + 1 box = 3.4
1 tank + 2.2 = 3.4
1 tank = 3.4 - 2.2 = 1.2
Mass of 1 tank = 1.2 kg
Mass of 1 tank less than 1 box
= 2.2 - 1.2
= 1 kg
Answer(s): (a) 3.4 kg; (b) 15.4 kg; (c) 1 kg