The petrol tank of Japheth's convertible was 55% empty. He went to the petrol kiosk and topped up 15 ℓ of petrol. When he reached the hypermart, the petrol tank was 70% full. Given that he used 5 ℓ of fuel to get to the hypermart from the kiosk, find the capacity of the petrol tank.
| |
Full |
Empty |
Total |
| Before |
9x1 =
9 u |
11x1 =
11 u |
20x1 =
20 u |
| Change 1 |
+ 15 |
- 15 |
|
| Change 2 |
- 5 |
+ 5 |
|
| After |
7x2 =
14 u |
3x2 =
6 u |
10x2 =
20 u |
55% =
55100 =
1120 Empty : Total = 11 : 20
70% =
70100 =
710 Full : Total = 7 : 10
The full capacity of the petrol tank is unchanged.
Make the totals the same. LCM of 20 and 10 is 20.
Volume of petrol in the end
= 9 u + 15 - 5
= 9 u + 10
14 u = 9 u + 10
14 u - 9 u = 10
5 u = 10
1 u = 10 ÷ 5 = 2
Capacity of the petrol tank
= 20 u
= 20 x 2
= 40 ℓ
Answer(s): 40 ℓ
