The petrol tank of Vaidev's sports car was 75% empty. He went to the petrol kiosk and topped up 37 ℓ of petrol. When he reached the hospital, the petrol tank was 95% full. Given that he used 9 ℓ of fuel to get to the hospital from the kiosk, find the capacity of the petrol tank.
| |
Full |
Empty |
Total |
| Before |
1x5 =
5 u |
3x5 =
15 u |
4x5 =
20 u |
| Change 1 |
+ 37 |
- 37 |
|
| Change 2 |
- 9 |
+ 9 |
|
| After |
19x1 =
19 u |
1x1 =
1 u |
20x1 =
20 u |
75% =
75100 =
34 Empty : Total = 3 : 4
95% =
95100 =
1920 Full : Total = 19 : 20
The full capacity of the petrol tank is unchanged.
Make the totals the same. LCM of 4 and 20 is 20.
Volume of petrol in the end
= 5 u + 37 - 9
= 5 u + 28
19 u = 5 u + 28
19 u - 5 u = 28
14 u = 28
1 u = 28 ÷ 14 = 2
Capacity of the petrol tank
= 20 u
= 20 x 2
= 40 ℓ
Answer(s): 40 ℓ
