Question

My Scooty gives an average of 40 kmpl of petrol. But after recent filling at the new petrol pump, its average dropped to 38 kmpl. I investigated and found out that it was due to adulterated petrol. Petrol pumps add kerosene, which is \(\frac{2}{3}\) cheaper than petrol, to increase their profits. Kerosene generates excessive smoke and knocking and gives an average of 18 km per 900 ml. If I paid Rs. 30 for a litre of petrol, what was the additional amount the pump-owner was making ?

• A. Rs. 1.75
• B. Rs. 1.80
• C. Rs. 2.30
• D. Rs. 2

Answer 1

The Correct Option is D

In the question it is given that the Capacity of Kerosene=(18 ÷900) ×1000=20km/ltr
Cost of Petrol is given=Rs.30/ltr
Cost of Kerosene= \(\frac{2}{3}\)(Cheaper than Petrol)=\(\frac{1}{3}\) (Petrol)
Cost of Kerosene = \(\frac{1}{3}\)(30) = Rs.10/ltr
Let take the Quantity of Kerosene is x ltr in 1 ltr of mixture
The capacity of Kerosene=20km/ltr
The capacity of Petrol=40km/ltr
If there is x Ltr Petrol in 1 Ltr
Then,
20(x)+40(1-x)=38
20x + 40 - 40x = 38
Solving the equation, we get
x = -\(\frac{-2}{-20}\)
x = 0.1 ltr 
The Cost of mixture will be = 10(.1) +30(.9)=Rs.28
The Cost of Petrol which I gave was Rs.30 but the Original Amount is Rs.28
Than, the Additional Amount that the Pump Owner was Charging
=Rs.30-Rs.28
= Rs.2
The correct option is (D)