The price of fuel decreases by 10%, 50% and 50% in three successive months, but increases by 45% in the fourth month. What is the percentage increase/decrease in the price of fuel in the fourth month as compared to its original price?

Correct option is C

​Given:
Original price of fuel = Rs. 100 (Assumed for calculation)
​First month: Decrease by 10%
​Second month: Decrease by 50%
​Third month: Decrease by 50%
​ Fourth month: Increase by 45%
​Formula Used:
​​$$\text{New Price} = \text{Previous Price} \times \left(1 + \frac{\text{Percentage Change}}{100}\right)$$​​​
​Solution:
​Price after 10% decrease = 100 × (1 - 0.10) = 100 × 0.90 = 90
​Price after 50% decrease = 90 × (1 - 0.50) = 90 × 0.50 = 45
​Price after 50% decrease = 45 × (1 - 0.50) = 45 × 0.50 = 22.5
​Price after 45% increase =22.5 × (1 + 0.45) = 22.5 × 1.45 = 32.625
​The price at the end of the fourth month is Rs. 32.625, compared to the original price of Rs. 100.
​Percentage Change = $$\left( \frac{32.625 - 100}{100} \right) \times 100 = -67.375\% \approx -67.38\%$$