The petrol tank of Wesley's sports car was 60% empty. He went to the petrol station and topped up 34 ℓ of petrol. When he reached the cinema, the petrol tank was 95% full. Given that he used 1 ℓ of fuel to get to the cinema from the kiosk, find the capacity of the petrol tank.
|
Full |
Empty |
Total |
Before |
2x4 = 8 u |
3x4 = 12 u |
5x4 = 20 u |
Change 1 |
+ 34 |
- 34 |
|
Change 2 |
- 1 |
+ 1 |
|
After |
19x1 = 19 u |
1x1 = 1 u |
20x1 = 20 u |
60% =
60100 =
35 Empty : Total = 3 : 5
95% =
95100 =
1920 Full : Total = 19 : 20
The full capacity of the petrol tank is unchanged.
Make the totals the same. LCM of 5 and 20 is 20.
Volume of petrol in the end
= 8 u + 34 - 1
= 8 u + 33
19 u = 8 u + 33
19 u - 8 u = 33
11 u = 33
1 u = 33 ÷ 11 = 3
Capacity of the petrol tank
= 20 u
= 20 x 3
= 60 ℓ
Answer(s): 60 ℓ