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:
The Target Test Prep course represents a quantum leap forward in GMAT preparation, a radical reinterpretation of the way that students should study. Try before you buy with a 5-day, full-access trial of the course for FREE!
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors
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.
U are right. This is a unique case of Binomial Distn. nCr.p^r.(1-p)^ (n-r)
here n = total number of tosses [here n]
r = no. of times desired outcome is possible [here = n , all heads]
p = probability of the desired outcome [here 1/2 = p of head in each toss]
so nCn.(1/2)^n.(1-1/2)^(n-n) = (1/2)^n.
In much more simple terms - p(first coin head).p(2nd coin head).....p(nth coin head) = 1/2.1/2....n times = (1/2)^n
However it is always better to stick to the general concept as that can be used more smoothly in all cases. For Eg.
Whats the P of getting 4 sixers on rolling 6 dices.
using above funda.
n = 6
r = 4
p = 1/6
P = 6C4.(1/6)^4.(5/6)^2.
Another important property is
SIGMA[r = 0 to n] nCr.p^r.(1-p)^ (n-r) = 1
Thats the sum of all cases and hence probab is 1.
Please let me know if you have any comments.
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.