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 Your Progress
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.
Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
What do András from Hungary, Pablo from Mexico, Conner from the United States, Giorgio from Italy, Leo from Germany, and Rishab from India have in common? They all earned top scores on the GMAT Focus Edition using the Target Test Prep course!
Grab 20% off any Target Test Prep GMAT Focus plan during our Flash Sale. Just enter the coupon code FLASH20 at checkout to save up to $320. The offer ends on Tuesday, April 30.
After just 3 months of studying with the TTP GMAT Focus course, Conner scored an incredible 755 (Q89/V90/DI83) on the GMAT Focus. In this live interview, he shares how he achieved his outstanding 755 (100%) GMAT Focus score on test day.
In this conversation with Ankit Mehra, IESE MBA and CEO & Co-Founder, of GyanDhan, we will discuss how prospective MBA students can finance their MBA education with education loans and scholarships.
What do András from Hungary, Conner from the United States, Giorgio from Italy, Leo from Germany, and Saahil from India have in common? They all earned top scores on the GMAT Focus Edition using the Target Test Prep course!
Another Cards Problem
[#permalink]
25 May 2012, 13:19
I take advantage of this first post to say hi to the GMAT Club which I find very interesting and useful.
I experience some difficulties with a simple probability problem found in the book "Conquering GMAT Math and Integrated Reasoning":
"What is the probability that a card selected at random from a standard deck of playing cards will be a 7 or a club ?"
It's a example to illustrate some theory so there is no multiple choice but the answer is: "There are 52 cards in a deck. There are 13 each in hearts, clubs, spades, and diamonds. There are four 7s, one each in hearths, clubs, spades, and diamonds. Thus the 7 of clubs is counted twice , once as a club and once as a 7 There are 13 clubs plus tree 7s that are not clubs. P(7 or Club) = 16/52 = 4/13
My problem with this answer is actually the fact that this 7 of clubs isn't counted twice as announced : why doesn't this card count as a double chance of getting an expected card (7 or club) ? My natural answer would have been P= (13+4)/52 = 17/52
Thank by advance
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Still interested in this question? Check out the "Best Topics" block below for a better discussion on this exact question, as well as several more related questions.
Re: Another Cards Problem
[#permalink]
27 May 2012, 06:06
1
Kudos
Hi sinclairv,
It is by definition that Probability of an event = (number of favorable cases)/(exhaustive number of cases)
The number of favorable cases would be 16, 'cause even if 7 of club is picked - although it fulfills the criteria of being a club or being 7, it will be counted as 1 card only.
And therefore the probability is 16/52.
So, whenever dealing with probability questions, try to visualize a real life example...and it will make the problem easy.
Regards,
Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Re: Another Cards Problem
[#permalink]
25 May 2012, 14:07
I honestly don't know a great explanation for you other than use logic. You should not and cannot double something in a probability...at least in this setup. Just because a card meets multiple criteria it does not mean it needs to be counted multiple times.
The trick that they want you to catch on to is the fact that you CANNOT count the 7 of clubs twice.