If the price of gasoline increases by 25% and Ron intends to spend onl

For wondering minds, "Rs" in the solution above is short for "Rupee" - a monetary unit in India.

This is how I solved...

Let the initial cost of gas before the hike be $100/gal
Price hike given = 25%
=> New gas price per gallon is $125

Also given, Ron can only spend 15% more of what he used to afford. It is to be understood from the prompt that he was able to afford a full gallon (which means he used to get 1 gal of gas) before the hike. So, he was able to afford $100 before the hike but now he can only afford 15% more of $100. Therefore, he could only pay $115.

You get what you pay, so instead of getting a full gallon of gas, he will now only get 0.92 gal [For $125 you get 1 gal, for $115 - how many? => \(\frac{1}{125}\)*115].

Finally, find the percentage decrease in the amount of gas from before and now.

Percentage Decrease =\(\frac{0.92 - 1}{1}\)*100

Let price of gasoline earlier = 100

So price of gasoline Later = 125 (25% higher)

Let consumption earlier = 100
So total expense earlier = 100*100 = 10000

New total expense = 11500 (15% higher)
New consumption of gasoline = 11500/125 = 92

Now, the consumption has changed from 100 to 92

hence, 8% decrease

Answer: Option B

Let the consumption be C , price of petrol be X and quantity consumed Y
Than we have C=X*Y
After price increase we have 1.15C=1.25X*a*Y
Where a is the percent of quantity decreased
Solving the above two equations we have a=92% of 8 % decrease.

Initial price = $ 100
Increased price = $ 125

Initial expenditure = 100
New expenditure = 115

If he wants to reduce the consumption = {(125 - 115)/125} * 100 = 8%

B

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