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.
Apr 25Crafting an Impactful Resume: Balancing Detail with Brevity
10:00 AM EDT
-10:30 AM EDT
Showcase your achievements through impactful storytelling! Get ready for an LIVE session on April 25, Learn how to craft compelling narratives on your resume that resonate with admission committees.
Apr 26Get a Top GRE Score with Target Test Prep
12:00 PM EDT
-01:00 PM EDT
The Target Test Prep course represents a quantum leap forward in GRE preparation, a radical reinterpretation of the way that students should study. In fact, more and more Target Test Prep students are scoring 329 and above on the GRE.
What is the probability of rolling a number less than 3 at l
[#permalink]
13 Aug 2020, 01:59
13 Aug 2020, 01:59
Expert Reply
13
Bookmarks
00:00
Question Stats:
52% (02:59) correct
47% (02:54) wrong based on 59 sessions
Hide Show timer Statistics
What is the probability of rolling a number less than 3 at least 3 times in 5 rolls of a six-sided die?
A. 2/15
B. 17/81
C. 1/3
D. 2/5
E. 15/32
KUDOS for the right solution and explanation
A. 2/15
B. 17/81
C. 1/3
D. 2/5
E. 15/32
KUDOS for the right solution and explanation
Re: What is the probability of rolling a number less than 3 at l
[#permalink]
13 Aug 2020, 16:35
13 Aug 2020, 16:35
4
2
Bookmarks
p= probability of rolling a number less than 3 = 2/6 =1/3
(namely rolling a 1 or 2 out of the 6 numbers)
Therefore
1-p= probability of not rolling a number less than 3 = 1-(1/3)= 2/3
Using Binomial Distribution
Case 1: Rolling a number less than 3 three times
(5 choose 3)*(p)^3*(1-p)^5-3= 5!/(2!3!) * (1/3)^3 * (2/3)^2 = 10(4/243) = 40/243
Case 2: Rolling a number less than 3 four times
(5 choose 4)*p^4 *(1-p)^5-4= 5!/(1!4!) * (1/3)^4 * (2/3)^1 = 5(2/243) = 10/243
Case 3: Rolling a number less than 3 five times
(5 choose 5)* p^5*(1-p)^0 = 5!/(0!5!)* (1/3)^5 * (2/3)^0 = 1*(1/243)(1)= 1/243
We add the probabilities of all the cases to get
40/243+ 10/243+ 1/243 = 51/243 = 17/81
Final Answer: B
(namely rolling a 1 or 2 out of the 6 numbers)
Therefore
1-p= probability of not rolling a number less than 3 = 1-(1/3)= 2/3
Using Binomial Distribution
Case 1: Rolling a number less than 3 three times
(5 choose 3)*(p)^3*(1-p)^5-3= 5!/(2!3!) * (1/3)^3 * (2/3)^2 = 10(4/243) = 40/243
Case 2: Rolling a number less than 3 four times
(5 choose 4)*p^4 *(1-p)^5-4= 5!/(1!4!) * (1/3)^4 * (2/3)^1 = 5(2/243) = 10/243
Case 3: Rolling a number less than 3 five times
(5 choose 5)* p^5*(1-p)^0 = 5!/(0!5!)* (1/3)^5 * (2/3)^0 = 1*(1/243)(1)= 1/243
We add the probabilities of all the cases to get
40/243+ 10/243+ 1/243 = 51/243 = 17/81
Final Answer: B
General Discussion
Re: What is the probability of rolling a number less than 3 at l
[#permalink]
15 Aug 2020, 04:07
15 Aug 2020, 04:07
1
Bookmarks
Carcass wrote:
What is the probability of rolling a number less than 3 at least 3 times in 5 rolls of a six-sided die?
A. 2/15
B. 17/81
C. 1/3
D. 2/5
E. 15/32
KUDOS for the right solution and explanation
A. 2/15
B. 17/81
C. 1/3
D. 2/5
E. 15/32
KUDOS for the right solution and explanation
@carcass can we solve this question using complement rule ??? if ues kindly show the solution in this way
