It is currently 23 Oct 2017, 12:32

### 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

# mathematics course

Author Message
Intern
Joined: 10 Oct 2010
Posts: 6

Kudos [?]: [0], given: 2

### Show Tags

17 Oct 2010, 08:41
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 100% (01:25) wrong based on 1 sessions

### HideShow timer Statistics

John and Mary are taking a mathematics course. The course has only three
grades: A, B, and C. The probability that John gets a B is .3. The probability
that Mary gets a B is .4. The probability that neither gets an A but at least
one gets a B is .1. What is the probability that at least one gets a B but
neither gets a C?

Kudos [?]: [0], given: 2

Senior Manager
Status: Time to step up the tempo
Joined: 24 Jun 2010
Posts: 404

Kudos [?]: 250 [0], given: 50

Location: Milky way
Schools: ISB, Tepper - CMU, Chicago Booth, LSB

### Show Tags

23 Oct 2010, 19:31
abeer16 wrote:
John and Mary are taking a mathematics course. The course has only three
grades: A, B, and C. The probability that John gets a B is .3. The probability
that Mary gets a B is .4. The probability that neither gets an A but at least
one gets a B is .1. What is the probability that at least one gets a B but
neither gets a C?

Phew. Could not crack this question even after trying it for 10 minutes. Bunuel/Shrouded/Other GMATClub members -- Could you please help here?

Side note: How to bump up a thread??? Should someone just reply or is there a way to do it without replying to the post?
_________________

Support GMAT Club by putting a GMAT Club badge on your blog

Kudos [?]: 250 [0], given: 50

Retired Moderator
Joined: 02 Sep 2010
Posts: 793

Kudos [?]: 1187 [0], given: 25

Location: London

### Show Tags

23 Oct 2010, 20:30
I am not convinced that this question is correct

P(neither a and at least one b) = P(both b) + P(one b, one c)

But, P(both b)=0.3*0.4=0.12>0.1

So this probability cannot be 0.1

Posted from my mobile device
_________________

Kudos [?]: 1187 [0], given: 25

Re: mathematics course   [#permalink] 23 Oct 2010, 20:30
Display posts from previous: Sort by