Forum Home > GMAT > Quantitative > Problem Solving (PS)
Events & Promotions
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Oct 0309:00 AM PDT
-12:00 PM PDT
Are you ready to take the next step in your academic and professional journey? If you’re aspiring to join one of the top 15 MBA programs, we’ve got an exciting opportunity just for you! Welcome to the GMAT Club's Free Interview Prep Event
Oct 0301:30 PM IST
-11:30 PM IST
With brand new features like:AI-driven Planner tool, 850+ data Insights practice questions and GMAT Focus Edition Adaptive mock tests with ESR+ analysis and personal mentor support, our course is the most comprehensive course for GMAT Focus Edition.- Oct 05
11:00 AM IST
-01:00 PM IST
Attend this session to learn how to Deconstruct arguments, Pre-Think Author’s Assumptions, and apply Negation Test. - Oct 06
11:00 AM IST
-01:00 PM IST
Attend this free GMAT Algebra Webinar and learn how to master the most challenging Inequalities and Absolute Value problems with ease. 
Oct 1010:00 AM EDT
-11:00 AM EDT
Have you ever wondered how to score a PERFECT 805 on the GMAT? Meet Julia, a banking professional who used the Target Test Prep course to achieve this incredible feat. Julia's story is nothing short of an inspiration.
Oct 1110:00 AM EDT
-11:00 AM EDT
Think a 100% GMAT Verbal score is out of your reach? Target Test Prep will make you think again! Our course uses techniques such as topical study and spaced repetition to maximize knowledge retention and make studying simple and fun.
Danny, Doris and Dolly flipped a fair coin 5 times and each time the
[#permalink]
28 Jan 2021, 13:21
28 Jan 2021, 13:21
2
Bookmarks
Expert Reply
Show timer
00:00
A
B
C
D
E
Difficulty:
5%
(low)
Question Stats:
100% (00:33) correct
0%
(00:00)
wrong
based on 90
sessions
Danny, Doris and Dolly flipped a fair coin 5 times and each time the coin landed on “heads”. Dolly bet that on the sixth time the coin will land on “tails”, what is the probability that she’s right?
A. 1
B. 3/4
C. 1/2
E. 1/3
D. 1/4
A. 1
B. 3/4
C. 1/2
E. 1/3
D. 1/4
Joined: 05 Jul 2020
Posts: 101
Given Kudos: 36
Location: India
Concentration: Leadership, General Management
GMAT 1: 650 Q49 V30 
GMAT 2: 730 Q48 V41 (Online)
GPA: 3.8
Danny, Doris and Dolly flipped a fair coin 5 times and each time the
[#permalink]
28 Jan 2021, 19:28
28 Jan 2021, 19:28
We are given that the coin landed on heads 5 times. Also, the coin is fair and for a fair coin, the probability of tails will be 1/2 for each flip as each flip is an independent event.
So for the 6th flip as well the probability that the coin will give tails is 1/2
Answer: C
So for the 6th flip as well the probability that the coin will give tails is 1/2
Answer: C
e-GMAT Representative
Joined: 04 Jan 2015
Posts: 3703
Given Kudos: 165
Re: Danny, Doris and Dolly flipped a fair coin 5 times and each time the
[#permalink]
31 Jan 2021, 06:18
31 Jan 2021, 06:18
Expert Reply
Solution
Given
In this question, we are given that
- • A coin landed on “heads” on 5 consecutive flips
To find
We need to determine
- • The probability that the sixth flip will also result in “heads”
Approach and Working out
- • Since the coin is a “fair” coin, no matter how many times we flip it, the probability of it landing on “heads” will always be ½.
- o No past outcomes can affect this probability since each flip of the coin is an independent experiment.
o The result of each flip can be “heads” or “tails” with equal probability. (1/2 each)
Thus, option C is the correct answer.
Correct Answer: Option C
