There was a series of two successive discounts of x% on the price

Question

There was a series of two successive discounts of x% on the price of a shirt. The final price of
the shirt was tagged at 36% of the original price. What is the value of x?

billionaire · Answer

Hi  gunavat

100 x 0.6= 60 60x0.6= 36

So that's short multiplication for 40% discount, two times in a row to get 36% of original price.

Questions should say that that two successive discounts of x% are equal, so that is more clear what questions is actually asking.

Answer is 40% discount, two times in a row.

I picked number 100, so I don't have to deal with two unknowns, that trick comes handy in this question.

What is the source of this question ?

pushpitkc · Answer

If the price of the shirt is 1, 36% of the original price will be 0.36

Hey  gunavat

Welcome to GMATClub!
Please follow the  RULES  of the forum while posting questions.

Since we are talking of two successive discounts of x%,  \frac{x}{100} * \frac{x}{100} * 1 = 0.36 
Since we need the value of x,  \frac{x^2}{10000} = 0.36  ->  x^2 = 3600  ->  x = \sqrt{3600} = 60

Hope this helps you!

Sauhaan · Answer

Hey  billionaire , 
But how you get 40%. Can u elaborate plz.

I understand up to x=60 as 100*60/100*60/100=36.
But didn't understand how to reach 40%.
The question source is from Jamboree.
Can u help me  Bunuel  sir

billionaire · Answer

Hi Sauhaan You will need to notice that from \sqrt{0.36} you can only get two consecutive multipliers as 0.6 * 0.6= 0.36 Now, you are asking why 0.6 as multiplier corresponds with 40% discount ? You will need to know that in order to discount any price with 40% you will need to multiply it with 0.6 as shortcut, since 1-0.4=0.6 I am sure this helps

ScottTargetTestPrep · Answer

Solution:

Let the original price of the shirt be $100 before any discounts. So the final price of the shirt is $36 after two successive discounts of x%. We can create the equation:

100 * (1 - x/100) * (1 - x/100) = 36

(1 - x/100)^2 = 36/100

1 - x/100 = √(36/100)

1 - x/100 = 6/10

4/10 = x/100

10x = 400

x = 40

Answer: 40

There was a series of two successive discounts of x% on the price

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards