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

 It is currently 16 Oct 2019, 23:29 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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.  One number, n, is selected at random from a set of 10 integers. What

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

Hide Tags

Math Expert V
Joined: 02 Sep 2009
Posts: 58401
One number, n, is selected at random from a set of 10 integers. What  [#permalink]

Show Tags 00:00

Difficulty:   55% (hard)

Question Stats: 59% (01:55) correct 41% (01:38) wrong based on 183 sessions

HideShow timer Statistics

One number, n, is selected at random from a set of 10 integers. What is the probability that 1/2*n + 13 = 0 ?

(1) The largest integer in the set is 13.
(2) The arithmetic mean of the set is zero.

_________________
Math Expert V
Joined: 02 Aug 2009
Posts: 7960
Re: One number, n, is selected at random from a set of 10 integers. What  [#permalink]

Show Tags

1
1
Bunuel wrote:
One number, n, is selected at random from a set of 10 integers. What is the probability that 1/2*n + 13 = 0 ?

(1) The largest integer in the set is 13.
(2) The arithmetic mean of the set is zero.

The Q can be rephrased-
$$\frac{1}{2}* n + 13 =0............n=-13*2=-26$$...............
so there are 10 integers and we have to find that what is the probability of the integer,n, being picked to be -26....
HAD the Q said been - a set of 10 DIFFERENT integers, our answer would be 1/10, but we do not know how many of 10 integers are -26...

(1) The largest integer in the set is 13.
we do not know anything about other 9 numbers
Insuff

(2) The arithmetic mean of the set is zero.

It just tells us that mean is 0, can be any variation..

Combined-
lot of variation can be made where the largest number is 13 and the mean is 0..
example 13,13,0,0,0,0,0,0,0,-26... prob = 1/10
13, 10,10,10,3,3,3,0,-26,-26..... Now prob = 2/10
Insuff
E
_________________
Board of Directors P
Joined: 17 Jul 2014
Posts: 2513
Location: United States (IL)
Concentration: Finance, Economics
GMAT 1: 650 Q49 V30 GPA: 3.92
WE: General Management (Transportation)
Re: One number, n, is selected at random from a set of 10 integers. What  [#permalink]

Show Tags

I picked E...a tricky one..
i initially thought we have consecutive integers, but then read second statement, and immediately knew that we can't find the answer...
Manager  S
Joined: 17 Apr 2016
Posts: 79
Re: One number, n, is selected at random from a set of 10 integers. What  [#permalink]

Show Tags

chetan2u wrote:
Bunuel wrote:
One number, n, is selected at random from a set of 10 integers. What is the probability that 1/2*n + 13 = 0 ?

(1) The largest integer in the set is 13.
(2) The arithmetic mean of the set is zero.

The Q can be rephrased-
$$\frac{1}{2}* n + 13 =0............n=-13*2=-26$$...............
so there are 10 integers and we have to find that what is the probability of the integer,n, being picked to be -26....
HAD the Q said been - a set of 10 DIFFERENT integers, our answer would be 1/10, but we do not know how many of 10 integers are -26...

(1) The largest integer in the set is 13.
we do not know anything about other 9 numbers
Insuff

(2) The arithmetic mean of the set is zero.

It just tells us that mean is 0, can be any variation..

Combined-
lot of variation can be made where the largest number is 13 and the mean is 0..
example 13,13,0,0,0,0,0,0,0,-26... prob = 1/10
13, 10,10,10,3,3,3,0,-26,-26..... Now prob = 2/10
Insuff
E

chetan2u,
For Statement A, I agree that the probability of choosing -26 would have been 1/10, but this would again be the case provided that it is given that -26 is a part of the set.
Manager  B
Joined: 03 Aug 2018
Posts: 66
Location: India
Concentration: Strategy, Operations
GMAT 1: 590 Q45 V26 GPA: 3.5
Re: One number, n, is selected at random from a set of 10 integers. What  [#permalink]

Show Tags

chetan2u wrote:
Bunuel wrote:
One number, n, is selected at random from a set of 10 integers. What is the probability that 1/2*n + 13 = 0 ?

(1) The largest integer in the set is 13.
(2) The arithmetic mean of the set is zero.

The Q can be rephrased-
$$\frac{1}{2}* n + 13 =0............n=-13*2=-26$$...............
so there are 10 integers and we have to find that what is the probability of the integer,n, being picked to be -26....
HAD the Q said been - a set of 10 DIFFERENT integers, our answer would be 1/10, but we do not know how many of 10 integers are -26...

(1) The largest integer in the set is 13.
we do not know anything about other 9 numbers
Insuff

(2) The arithmetic mean of the set is zero.

It just tells us that mean is 0, can be any variation..

Combined-
lot of variation can be made where the largest number is 13 and the mean is 0..
example 13,13,0,0,0,0,0,0,0,-26... prob = 1/10
13, 10,10,10,3,3,3,0,-26,-26..... Now prob = 2/10
Insuff
E

chetan2u,
For Statement A, I agree that the probability of choosing -26 would have been 1/10, but this would again be the case provided that it is given that -26 is a part of the set.

I have the same question, any reasons that we can say probability would be 1/10 if in case n were categorically mentioned as dufferent integers ?

chetan2u , Bunuel - advice please ? Re: One number, n, is selected at random from a set of 10 integers. What   [#permalink] 16 Oct 2018, 06:11
Display posts from previous: Sort by

One number, n, is selected at random from a set of 10 integers. What

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne  