The petrol tank of Caden's lorry was 65% empty. He went to the petrol kiosk and topped up 32 ℓ of petrol. When he reached the mall, the petrol tank was 80% full. Given that he used 5 ℓ of fuel to get to the mall from the kiosk, find the capacity of the petrol tank.
| |
Full |
Empty |
Total |
| Before |
7x1 =
7 u |
13x1 =
13 u |
20x1 =
20 u |
| Change 1 |
+ 32 |
- 32 |
|
| Change 2 |
- 5 |
+ 5 |
|
| After |
4x4 =
16 u |
1x4 =
4 u |
5x4 =
20 u |
65% =
65100 =
1320 Empty : Total = 13 : 20
80% =
80100 =
45 Full : Total = 4 : 5
The full capacity of the petrol tank is unchanged.
Make the totals the same. LCM of 20 and 5 is 20.
Volume of petrol in the end
= 7 u + 32 - 5
= 7 u + 27
16 u = 7 u + 27
16 u - 7 u = 27
9 u = 27
1 u = 27 ÷ 9 = 3
Capacity of the petrol tank
= 20 u
= 20 x 3
= 60 ℓ
Answer(s): 60 ℓ
