Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 04 May 2015, 10:55

### 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

# From a set of cards numbered 1 to 20 a card is drawn at

Author Message
TAGS:
Manager
Joined: 27 Jul 2003
Posts: 124
Location: Singapore
Followers: 1

Kudos [?]: 10 [0], given: 0

From a set of cards numbered 1 to 20 a card is drawn at [#permalink]  09 Oct 2003, 22:16
From a set of cards numbered 1 to 20 a card is drawn at random. Find the probability that the number is
a. is divisible by 4
b. is greater than 15
c. is divisible by 4 and greater than 15
If the card is divisible by 4 and it is not replaced, find the probability that
d. the second card drawn is even
SVP
Joined: 03 Feb 2003
Posts: 1608
Followers: 6

Kudos [?]: 76 [0], given: 0

a. 5 such numbers, so P=5/20=1/4
b. 5 such numbers, so P=5/20=1/4
c. 2 such numbers, so P=2/20=1/10
d. one even from 10 initial is out, so P=9/19
SVP
Joined: 30 Oct 2003
Posts: 1797
Location: NewJersey USA
Followers: 5

Kudos [?]: 41 [0], given: 0

Hi stolyar,

Shouldn't the probability of the last question be
5/20 * 9/19
( Probability that card is divisible by4 ) * ( probability that card is even )

if this is not correct then please provide an explaination. It is so frustrating that araspai has not posted the answer.
GMAT Instructor
Joined: 07 Jul 2003
Posts: 770
Location: New York NY 10024
Schools: Haas, MFE; Anderson, MBA; USC, MSEE
Followers: 13

Kudos [?]: 52 [0], given: 0

anandnk wrote:
Hi stolyar,

Shouldn't the probability of the last question be
5/20 * 9/19
( Probability that card is divisible by4 ) * ( probability that card is even )

if this is not correct then please provide an explaination. It is so frustrating that araspai has not posted the answer.

No. We are already GIVEN that the first card is divisible by 4. Hence, it already happened with probability 1.
_________________

Best,

AkamaiBrah
Former Senior Instructor, Manhattan GMAT and VeritasPrep
Vice President, Midtown NYC Investment Bank, Structured Finance IT
MFE, Haas School of Business, UC Berkeley, Class of 2005
MBA, Anderson School of Management, UCLA, Class of 1993

Similar topics Replies Last post
Similar
Topics:
The cards in a deck are numbered consecutively from 1 to 20. 3 16 Oct 2010, 04:47
20 cards are numbered 1-20 and drawn randomly from a hat and 9 10 Feb 2007, 14:32
A deck of cards contains 10 cards numbered from 1 to 10. 6 02 Aug 2006, 09:04
1) Cards are drawn (without replacement) from a deck (of 52 6 27 Mar 2006, 17:50
A Bin contains card numbered from 1 to 20. If two cards are 7 03 Jun 2005, 14:43
Display posts from previous: Sort by