GRE Prep 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.
Flipping a fair two-sided coin, the probability of getting
[#permalink]
Updated on: 22 Jul 2020, 00:53
Updated on: 22 Jul 2020, 00:53
1
1
Bookmarks
00:00
Question Stats:
82% (00:59) correct
17% (00:53) wrong based on 17 sessions
Hide Show timer Statistics
Flipping a fair two-sided coin, the probability of getting heads is equal to the probability of getting tails. If the coin is flipped three times consecutively, what is the probability of getting heads at least twice?
Show: :: OA
0.5
Moderator
Joined: 02 Jan 2020
Status:GRE Quant Tutor
Posts: 1115
Given Kudos: 9
Location: India
Concentration: General Management
Schools: XLRI Jamshedpur, India - Class of 2014
GMAT 1: 700 Q51 V31
GPA: 2.8
WE:Engineering (Computer Software)
Flipping a fair two-sided coin, the probability of getting
[#permalink]
22 Jul 2020, 07:16
22 Jul 2020, 07:16
3
1
Bookmarks
When we toss a fair two-sided coin then we have equal probability of getting head/tail in each toss
So. P(T) = P(H) = 0.5
Now, we are tossing the coin three times so we will get a total of \(2^3 \)= 8 cases.
Refer below image to understand the 8 cases
Image.jpg [ 32.26 KiB | Viewed 4436 times ]
We ween to find the probability that we get at least 2 heads, i.e. 2 or more heads
So, there are four cases (highlighted in the image) where we will have 2 or more heads
=> P(At least 2 heads) = \(\frac{4}{8}\) = 0.5
So, Answer will be 0.5
Hope it helps!
Watch the following video to learn How to Solve Probability with Coin Toss Problems
So. P(T) = P(H) = 0.5
Now, we are tossing the coin three times so we will get a total of \(2^3 \)= 8 cases.
Refer below image to understand the 8 cases
Attachment:
Image.jpg [ 32.26 KiB | Viewed 4436 times ]
We ween to find the probability that we get at least 2 heads, i.e. 2 or more heads
So, there are four cases (highlighted in the image) where we will have 2 or more heads
=> P(At least 2 heads) = \(\frac{4}{8}\) = 0.5
So, Answer will be 0.5
Hope it helps!
Watch the following video to learn How to Solve Probability with Coin Toss Problems
General Discussion
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: Flipping a fair two-sided coin, the probability of getting
[#permalink]
22 Jul 2020, 07:08
22 Jul 2020, 07:08
2
Farina wrote:
Flipping a fair two-sided coin, the probability of getting heads is equal to the probability of getting tails. If the coin is flipped three times consecutively, what is the probability of getting heads at least twice?
Show: :: OA
0.5
One approach here is to simply list all 8 possible outcomes (in a systematic way):
HHH
HHT
HTH
HTT
THH
THT
TTH
TTT
Among the 8 possible outcomes, 4 are such that we have at least two heads.
So, P(at least two heads) = 4/8 possible outcomes = 1/2
Answer: 0.5
Cheers,
Brent
