The petrol tank of Daniel's convertible was 60% empty. He went to the petrol station and topped up 25 ℓ of petrol. When he reached the temple, the petrol tank was 85% full. Given that he used 7 ℓ of fuel to get to the temple 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 |
+ 25 |
- 25 |
|
| Change 2 |
- 7 |
+ 7 |
|
| After |
17x1 =
17 u |
3x1 =
3 u |
20x1 =
20 u |
60% =
60100 =
35 Empty : Total = 3 : 5
85% =
85100 =
1720 Full : Total = 17 : 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 + 25 - 7
= 8 u + 18
17 u = 8 u + 18
17 u - 8 u = 18
9 u = 18
1 u = 18 ÷ 9 = 2
Capacity of the petrol tank
= 20 u
= 20 x 2
= 40 ℓ
Answer(s): 40 ℓ
