The petrol tank of Fabian's convertible was 65% empty. He went to the petrol station and topped up 32 ℓ of petrol. When he reached the hypermart, the petrol tank was 75% full. Given that he used 8 ℓ of fuel to get to the hypermart 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 |
- 8 |
+ 8 |
|
After |
3x5 = 15 u |
1x5 = 5 u |
4x5 = 20 u |
65% =
65100 =
1320 Empty : Total = 13 : 20
75% =
75100 =
34 Full : Total = 3 : 4
The full capacity of the petrol tank is unchanged.
Make the totals the same. LCM of 20 and 4 is 20.
Volume of petrol in the end
= 7 u + 32 - 8
= 7 u + 24
15 u = 7 u + 24
15 u - 7 u = 24
8 u = 24
1 u = 24 ÷ 8 = 3
Capacity of the petrol tank
= 20 u
= 20 x 3
= 60 ℓ
Answer(s): 60 ℓ