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

Question

If the price of gasoline increases by 25% and Ron intends to spend only 15% more on gasoline, by how much percent should he reduce the quantity of gasoline that he buys?

A. 6.66%
B. 8%
C. 10%
D. 12%
E. 12.5%

GMATinsight · Accepted Answer

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

Skywalker18 · Answer

Let price of original price of gasoline = 10$
and let original consumption of gasoline = 10
Amount spend on gasoline originally = 10*10 = 100$

the price of gasoline increases by 25% and Ron intends to spend only 15% more on gasoline
Increased price of gasoline = 12.5$
Now Ron intends to spend on gasoline =1.15*100 = 115$
Consumption of gasoline needs to be = 115/12.5
= 1150/125 
= 46/5 = 9.2
Reduction in consumption of gasoline = 10-9.2 = .8
% reduction in consumption of gasoline = .8/10 * 100%
= 8%
Answer B

rohit8865 · Answer

Let he consumes 10 ltr  RS  10 so he spends Rs 100
As er question he intends to spend 15% more (of 100 in our case)=Rs 115
and price increased by 25% =Rs. 12.5 (10+25% of 10)
let he reduces quantity by X lts. then consumed(new reduced) quantity= 10(1-X/100)
Spending amount=Price of gasoline*Quantity
115=12.5*10(1-X/100)
X=8%
Ans B

Blackbox · Answer

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  \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

arvind910619 · Answer

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.

KanishkM · Answer

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

AkiWho · Answer

I did:
25 - x - (25*x/100) = 15

Solved it, got x = 8.

Ans -  Option B: 8%

Thoughts?

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

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