A store owner decided to raise the price of a particular

10% increase = 1.1x where x is the original amount.
1.1 = 11/10. So the answer must be a multiple of 11.
Only answer choice that is not a multiple of 11 is D.

Hence D

Hope it helps!
Cheers
J

Hi All,

This question has a great "pattern-matching" shortcut built into it, but you'll have to pay attention to the answer choices to see it.

We're told that a store owner raises the price of an item by 10%. We're asked which of the 5 answers could NOT possibly be the new price.

In this scenario, it's real easy to come up with a simple example of what the store owner did.

IF....
price = $1, then new price = $1.10

You'll notice that answer is Answer A.

Answer B is just 8 times $1.10, which makes sense because 10% of 8 is 0.80...

IF...
price = $8, then new price = $8.80

So the shortcut is just to find the answers that are multiples of $1.10

Answer C is another quick "find" - it's 10 times $1.10

Between D and E, you have to do a little work, but if you "break down" E, you get....

78.10 = 77.00 + 1.10

77.00 = 70 + 7 (which is 10% of 70)
1.10 = 1 + 0.1 (which is 10% of 1)
So E is another multiple of $1.10

That leaves just one answer....

Final Answer:

GMAT assassins aren't born, they're made,
Rich

Ok taking your way -

Let price be x { we do not know whether it is even / odd/ integer / whole number}

The store owner decided to raise the price of a particular item by exactly 10%, so the new price must be x *110 /100 =>1.1x

So, The new number must be 1.1 times the original price.

Now, check option (D)

1.1x = 57.30
So, x = 57.30/1.1 ~ 52.09 (Approximately)

But the Same is not with option (E)

1.1x = 78.10
x = 71

So IMHO (D) does not fall into the group....

Hi stonecold,

Abhishek is right. Option D is correct.

When 573 is divided by 11 we get a remainder 1.
1/11 is non terminating and the question states that the increase is exactly 10%.

Since the value is non terminating, original price cannot be accurately determined. The original value can be 52.0909090909.........................

Hi stonecold,

This question is still 'restricted' to the reality of 'dollars and cents.' While Answer D could be divided by 1.1, you would end up with a repeating decimal in the original price of that item. Regardless of how hard you look, you will never find a store that charges you a price that includes a repeating decimal.

GMAT assassins aren't born, they're made,
Rich

But (8+0)-(7+1)=0, and zero isn't divisble by 11, either. Is zero exempt from the rule?

Zero is divisible by EVERY integer except zero itself, since 0/integer=integer.

Check for more number properties hints/tips/rules the link in my previous topic.

A 1 * 1.1 = 1.10 $
B 8 * 1.1 = 8.80 $
C 10* 1.1 = 11 $
D - strange Number
E 71 * 1.1 = 78.1 $

since D is the only answer, where I couldn't calculate the percents right away, I chose D.

BUT if the store owner had strange prices like 52.09 $ the new price would be 57.30 $. Is this a real GMAT question? Because it says nowhere that the original price has to be integer.

greetings

No, it doesn't and thats why the question is somewhat flawed

Cheers
J

Posted from my mobile device

Hey EMPOWERgmatRichC You are assuming here that the price is an INteger..
What if its NOT...
My Guess is => THIS IS A WRONG QUESTION AS ALL OPTIONS ARE POSSIBLE..

Let price be $ 10
The store owner decided to raise the price of a particular item by exactly 10%, so the new price must be 110 *10 /100 =>11

So, The new price must be a multiple of 11

From the given options check for all the multiples of 11

Test of divisibility of 11 is

" if the difference of the sum of digits at odd places and the sum of its digits at even places, is either 0 or divisible by 11, then clearly the number is divisible by 11."

A. $1.10
B. $8.80
C. $11.00

By a quick glance even a 2nd grader can eliminate options A,B and C , because they are all divisible by 11 , let with only 2 options check for the divisibility rule for options D and E

D. $57.30

Sum of even digits is 5+3 = 8
Sum of odd digits is 7 +0 = 7

Difference of the even and odd digits is 8 - 7 = 1 ; not divisible by 11

Hence this is our answer.

E. $78.10

Further inspection is not required since we have already found out the answer at (D)

stonecold No question of treating the number as integers / not take it as it is given in the question stem.

Completely DISAGREE
For non integers every answer works..

Is it so ? I never bothered to check that please provide us with your explanation..

Lets check again.

see
Every answer is valid Except D (as you put it) ..
D will be valid if => x= 573/11
Hence D will be valid too

Remember No one told us that x needs be an integer ..

Yes..Abhishek009
But the Question is Which of the following Cannot be the value of x
hence we cannot say which one.
x needs to be an integer here
P.S - We can play along all day .. Every value is valid unless stated otherwise
CC :- Vyshak

In this question, we need to determine the new price. The price must be 1.1 times of the old price.
However, there is one assumption in this question : The old price is a whole number.
With this assumption in mind, you will realise that the OA is D

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