GMAT Question of the Day: Daily via email | Daily via Instagram New to GMAT Club? Watch this Video

 It is currently 17 Jan 2020, 12:46 ### 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.  # Set V consists of 2 distinct positive values. What is the standard dev

Author Message
TAGS:

### Hide Tags

Math Expert V
Joined: 02 Sep 2009
Posts: 60460
Set V consists of 2 distinct positive values. What is the standard dev  [#permalink]

### Show Tags 00:00

Difficulty:   55% (hard)

Question Stats: 53% (01:15) correct 47% (01:19) wrong based on 58 sessions

### HideShow timer Statistics

Set V consists of 2 distinct positive values. What is the standard deviation of set V?

(1) The mean of the set is 10.
(2) The range of the set is 10.

Are You Up For the Challenge: 700 Level Questions

_________________
VP  V
Joined: 20 Jul 2017
Posts: 1231
Location: India
Concentration: Entrepreneurship, Marketing
WE: Education (Education)
Re: Set V consists of 2 distinct positive values. What is the standard dev  [#permalink]

### Show Tags

1
2
Bunuel wrote:
Set V consists of 2 distinct positive values. What is the standard deviation of set V?

(1) The mean of the set is 10.
(2) The range of the set is 10.

Are You Up For the Challenge: 700 Level Questions

Let the 2 distinct values of the set = {a, b} and a < b

(1) The mean of the set is 10.
Many values of {a, b} are possible = {1, 19} or {2, 18} or {2.5, 17.5} so on ...
--> We cannot find exact value of standard deviation --> Insufficient

(2) The range of the set is 10.
--> Many values of {a, b} are possible = {1, 11} or {2, 11} or {2.5, 12.5} so on ...
--> b = 10 + a
--> Set = {a, 10 + a}
Step 1: Mean = (a + 10 + a)/2 = 5 + a
Step 2: Deviations from Mean = {a - (5 + a), 10 + a - (5 + a)} = {-5, 5}
Step 3: Standard deviation = $$\sqrt{\frac{((-5)^2 + 5^2)}{2}} = \sqrt{\frac{50}{2}}= 5$$ --> Sufficient

IMO Option B
Manager  G
Joined: 10 Jun 2019
Posts: 119
Re: Set V consists of 2 distinct positive values. What is the standard dev  [#permalink]

### Show Tags

Statement 1 : the mean alone provides us insufficient information to find the SD

Statement 2 : Every set of 2 distinct numbers with a range of 10 will have the same SD=25. Sufficient Re: Set V consists of 2 distinct positive values. What is the standard dev   [#permalink] 02 Nov 2019, 05:41
Display posts from previous: Sort by

# Set V consists of 2 distinct positive values. What is the standard dev   