GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 23 Jun 2018, 03:33

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Which of two different jars, A and B, contain more candies?

Author Message
TAGS:

Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 46291
Which of two different jars, A and B, contain more candies? [#permalink]

Show Tags

08 Jan 2018, 07:37
00:00

Difficulty:

35% (medium)

Question Stats:

68% (00:38) correct 32% (00:21) wrong based on 37 sessions

HideShow timer Statistics

Which of two different jars, A and B, contain more candies?

(1) The average (arithmetic mean) weight of the candies in jar A is 2.5 grams and the average weight of the candies in jar B is 2.8 grams.
(2) When the two jars are combined in a third jar, C, the average weight is 2.7 grams.

_________________
PS Forum Moderator
Joined: 25 Feb 2013
Posts: 1142
Location: India
GPA: 3.82
Which of two different jars, A and B, contain more candies? [#permalink]

Show Tags

08 Jan 2018, 10:40
Bunuel wrote:
Which of two different jars, A and B, contain more candies?

(1) The average (arithmetic mean) weight of the candies in jar A is 2.5 grams and the average weight of the candies in jar B is 2.8 grams.
(2) When the two jars are combined in a third jar, C, the average weight is 2.7 grams.

Statement 1: let jar A contain $$x$$ candies and jar B contain $$y$$ candies. So total weight of Jar A $$=2.5x$$ & that of Jar B$$=2.8y$$. But we do not have any relation connecting these two weights, hence $$x$$ & $$y$$ cannot be calculated. Insufficient

Statement 2: No information to calculate number of candies in Jar A & B. Insufficient

Combining 1 & 2: we have $$2.5x+2.8y=2.7(x+y) => \frac{y}{x}=\frac{2}{1}$$. Hence Jar B has more candies. Sufficient

Option C
DS Forum Moderator
Joined: 22 Aug 2013
Posts: 1209
Location: India
Re: Which of two different jars, A and B, contain more candies? [#permalink]

Show Tags

08 Jan 2018, 11:23
Bunuel wrote:
Which of two different jars, A and B, contain more candies?

(1) The average (arithmetic mean) weight of the candies in jar A is 2.5 grams and the average weight of the candies in jar B is 2.8 grams.
(2) When the two jars are combined in a third jar, C, the average weight is 2.7 grams.

Based on the first statement, we cannot really say which jar has more candles. Based on second statement alone also, there is nothing to be said.

But when we combine the two statements, we see that the net average (weighted average) is inclined more towards average of jar B than towards average of jar A (combined average weight of 2.7 grams is closer to the average weight of jar B 2.8 grams than that of jar A which is 2.5 grams). Thus there are definitely more candles in jar B than in jar A.

Intern
Joined: 16 May 2017
Posts: 15
Location: India
GMAT 1: 770 Q51 V49
WE: Operations (Internet and New Media)
Re: Which of two different jars, A and B, contain more candies? [#permalink]

Show Tags

08 Jan 2018, 19:17
C should be the answer IMO, assuming all the candies have same weight.
DS Forum Moderator
Joined: 22 Aug 2013
Posts: 1209
Location: India
Re: Which of two different jars, A and B, contain more candies? [#permalink]

Show Tags

08 Jan 2018, 22:31
1
NikMan wrote:
C should be the answer IMO, assuming all the candies have same weight.

Hi

Its not necessary for all candles to have the same weight. Whether the weights of candles are same or different, if the combined average weight of the two jars is closer to a particular jar - then that jar has got more candles.

You can refer to the solution by niks18 posted above, which explains this thing algebraically.
Intern
Joined: 16 May 2017
Posts: 15
Location: India
GMAT 1: 770 Q51 V49
WE: Operations (Internet and New Media)
Re: Which of two different jars, A and B, contain more candies? [#permalink]

Show Tags

09 Jan 2018, 18:32
amanvermagmat wrote:
NikMan wrote:
C should be the answer IMO, assuming all the candies have same weight.

Hi

Its not necessary for all candles to have the same weight. Whether the weights of candles are same or different, if the combined average weight of the two jars is closer to a particular jar - then that jar has got more candles.

You can refer to the solution by niks18 posted above, which explains this thing algebraically.

@amanvermagmat- You are absolutely correct, the combined average will always sway towards the jar with the more candies. I also proved this with general weights acting alegbraically in a manner similar to niks18's.
Also, in retrospect, my statement above appears quite foolish. In case all the candies had the same weight, the average wt for all three bags would be that same wt only, irespective of the nos.
Thank-you very much for pointing this out.
Re: Which of two different jars, A and B, contain more candies?   [#permalink] 09 Jan 2018, 18:32
Display posts from previous: Sort by