Last visit was: 19 Nov 2025, 11:07

It is currently 19 Nov 2025, 11:07

Toolkit

Practice Tests

Quantitative Questions

Problem Solving (PS)

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

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.

Go to My Error Log Learn more

Request Expert Reply

Confirm Cancel

Nov 20
UCR MBA Impact - Live Q&A with UCR AdCom & Student
07:30 AM PST
-
08:30 AM PST
Learn what truly sets the UC Riverside MBA apart and how it helps in your professional growth
Nov 22
GMAT RC Masterclass
11:00 AM IST
-
01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment
Nov 23
Conquer Algebra on the GMAT Focus Edition
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.
Nov 25
Try OnDemand GMAT Masterclass
10:00 AM EST
-
11:00 AM EST
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.

bebu24

Joined: 19 May 2025

Last visit: 21 Aug 2025

Posts: 61

Own Kudos:

[2]

Given Kudos: 12

Posts: 61

Kudos: 35

[2]

01 Jul 2025, 02:38

Kudos

Bookmarks

Let there be n penguins and the probability for each penguin to complete the migration be p.
Now it is given in the question that, "the probability that all the penguins in a marine study group complete their annual migration is 0.05", which means:
p^n = 0.05.

IMO, we cannot derive the values of p and n from this.

what is being asked is " the probability that none of the penguins complete the migration?", which translates to:
(1-p)^n

Since we do not know the values of p and n, the answer should be E.

Bunuel

The probability that all the penguins in a marine study group complete their annual migration is 0.05. If each penguin has the same probability of completing the migration, what is the probability that none of the penguins complete the migration?

A. 0.05
B. 0.5
C. 0.75
D. 0.95
E. Cannot be determined from the given information

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

lemonwatermelo

Joined: 01 Aug 2021

Last visit: 17 Nov 2025

Posts: 13

Own Kudos:

[1]

Given Kudos: 127

Location: India

Concentration: International Business, Strategy

Schools: Duke '26 HBS '26 HEC Sept '26 INSEAD Aug '26 Kellogg '26 LBS '26 UNC '26 NUS '26 Ross '27 Yale '26

GPA: 8

Products:

Schools: Duke '26 HBS '26 HEC Sept '26 INSEAD Aug '26 Kellogg '26 LBS '26 UNC '26 NUS '26 Ross '27 Yale '26

Posts: 13

Kudos: 6

[1]

01 Jul 2025, 02:41

Kudos

Bookmarks

Let the probability that a single penguin completes the migration= p
And number of penguins= n

So, probability that all penguins complete migration = p^n = 0.05.
Then probability that none complete the migration = (1 - p)^n.

Since we don't know p or n, we cannot determine (1 - p)^n (or probability that none complete the migration).

Answer: E. Cannot be determined from the given information.

RashmikaAnumula35

Joined: 02 Sep 2024

Last visit: 19 Nov 2025

Posts: 8

Own Kudos:

[1]

Given Kudos: 21

Location: India

Posts: 8

Kudos: 1

[1]

01 Jul 2025, 02:42

Kudos

Bookmarks

The answer is E. Since we don't know the number of penguins

jkkamau

Joined: 25 May 2020

Last visit: 19 Nov 2025

Posts: 132

Own Kudos:

107

Given Kudos: 122

Location: Kenya

Schools: Haas '25

GMAT 1: 730 Q50 V46 Verified score

GPA: 3.5

Products:

Schools: Haas '25

GMAT 1: 730 Q50 V46 Verified score

Posts: 132

Kudos: 107

01 Jul 2025, 02:58

Kudos

Bookmarks

None (probability that none) = 1-(probability that all)
1-0.05 = 0.95
Ans D

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

Rahilgaur

Joined: 24 Jun 2024

Last visit: 19 Nov 2025

Posts: 104

Own Kudos:

[1]

Given Kudos: 45

GMAT Focus 1: 575 Q81 V82 DI72 Verified score

Products:

GMAT Focus 1: 575 Q81 V82 DI72 Verified score

Posts: 104

Kudos: 74

[1]

01 Jul 2025, 03:14

Kudos

Bookmarks

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

Probability that none of the penguins complete the migration + Probability that all of the penguins complete the migration + Probability that some of the penguins complete the migration and remaining did not (All possible combinations) = 1

Information to calculate the Probability that some of the penguins complete the migration and remaining did not (All possible combinations) is not available hence E

JOREDA1234

Joined: 18 Jun 2025

Last visit: 15 Aug 2025

Posts: 12

Own Kudos:

[1]

Posts: 12

Kudos: 11

[1]

01 Jul 2025, 03:46

Kudos

Bookmarks

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

So if probability of all penguins completeing their route is 0.05 and each penguin has the same probability to complete the migration, the probability required to complete is:

0.05 = P(Finishes migration)^n

Where P(Finishes migration) = Probability of a penguin to finish the migration
n = Number of penguins

Now if we have to find the probability that none of the penguins complete the migration. We take probability that penguin does not finish migration => 1-P(Finishes migration). So we will have

(1-P(Finishes migration))^n

Since we do not know the number of penguins, we cannot solve the problem.

saibharatmba

Joined: 23 May 2022

Last visit: 02 Sep 2025

Posts: 9

Own Kudos:

[1]

Given Kudos: 13

Location: India

Concentration: Strategy, Technology

GPA: 8.6

WE:Programming (Manufacturing)

Posts: 9

Kudos: 10

[1]

01 Jul 2025, 04:23

Kudos

Bookmarks

the probability that all penguins complete the migration is 0.05
Since the number of penguins is not provided, Correct option is E.

required probability = (1−(0.05)^1/n)^n (n is the number of penguins)

E. Cannot be determined from the given information

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

adityaprateek15

Joined: 26 May 2023

Last visit: 19 Nov 2025

Posts: 268

Own Kudos:

104

[1]

Given Kudos: 309

Location: India

Schools: Ross '26 Tepper '26 McCombs '26

GPA: 2.7

Products:

Schools: Ross '26 Tepper '26 McCombs '26

Posts: 268

Kudos: 104

[1]

01 Jul 2025, 05:24

Kudos

Bookmarks

P^n = 0.05

P (none of the penguins complete the migration) = (1-P)^n = ?

We don't have sufficient info to solve it further. Cannot be Determined.

Option E

muuss

Joined: 10 Aug 2024

Last visit: 19 Nov 2025

Posts: 108

Own Kudos:

[1]

Given Kudos: 38

GMAT Focus 1: 615 Q84 V81 DI76 Verified score

Products:

GMAT Focus 1: 615 Q84 V81 DI76 Verified score

Posts: 108

Kudos: 83

[1]

01 Jul 2025, 05:30

Kudos

Bookmarks

p(all penguins)=0.05
p(one penguin)=x
number of penguin not known, let it be n
p(no penguin)=1-x^n
1-x^n=0.05
0.95=x^n (since there are two unknown ans E)

mvgkannan

Joined: 23 Apr 2025

Last visit: 01 Oct 2025

Posts: 58

Own Kudos:

[1]

Given Kudos: 38

Location: India

Concentration: Finance, Entrepreneurship

Schools: CBS '26 Sloan '26 Wharton '26 HBS '26 Stanford '26 INSEAD Aug '26 LBS '26 ISB '26

GMAT Focus 1: 705 Q90 V85 DI80 Verified score

WE:General Management (Government)

Schools: CBS '26 Sloan '26 Wharton '26 HBS '26 Stanford '26 INSEAD Aug '26 LBS '26 ISB '26

GMAT Focus 1: 705 Q90 V85 DI80 Verified score

Posts: 58

Kudos: 36

[1]

01 Jul 2025, 05:33

Kudos

Bookmarks

So lets consider two cases,
case 1: the group is made of 2 penguin, since the probability of all the penguins completing is 0.05 and each penguin has same probability p, this implies p^2 = 0.05.
p = \sqrt{ 0.05 }) = 0.22/0.23. The probability of none of the penguin completes is calculated by (1-p)^2, which is 1+p^2 - 2p = 1.05 - \sqrt{ 0.05 }. = 0.82.

Case 2. The group is made of 100 penguins. then p^100 = 0.05, then p is almost close to 1. Then 1-p is almost 0, then probability of (1-p)^100 is further close to 0. Thus the value is different. Hence it cannot be calculated. Ans (E)

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

vnar12

Joined: 03 Jun 2024

Last visit: 26 Aug 2025

Posts: 51

Own Kudos:

[1]

Given Kudos: 4

Posts: 51

Kudos: 32

[1]

01 Jul 2025, 05:48

Kudos

Bookmarks

The answer is E - if the question says that the probability of the penguins all completing the migration is 0.05, we can interpret that number as 5% or 0.05 of 100. So therefore there is a 5% chance of all of the penguins completing the migration. If we look at the rest of the 100% leftover, there is 95%. However that 95% chance could include instances where some of the penguins complete the migration and some do not. We won't know exactly what the possibility of no penguins completing the migration would be, therefore the answer is E, cannot be determined.

professor805

Joined: 22 Apr 2023

Last visit: 01 Aug 2025

Posts: 3

Own Kudos:

[1]

Given Kudos: 8

Posts: 3

Kudos: 2

[1]

01 Jul 2025, 06:02

Kudos

Bookmarks

All penguins migrate is 5% - Given
Each penguin has the same chance of migrating. (5%) - Given

we don’t know how many penguins there are

To find the chance that none migrate, we need to know both:

Each penguin’s individual chance - 5% here
How many penguins there are - not provided

Since we don’t know the number of penguins, we can’t figure out the chance that none migrate. Answer E - Cannot be determined

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

Rishi705

Joined: 25 Apr 2024

Last visit: 19 Nov 2025

Posts: 44

Own Kudos:

[1]

Given Kudos: 20

Posts: 44

Kudos: 32

[1]

01 Jul 2025, 06:23

Kudos

Bookmarks

It depends on the number of penguins. If there is only 1 Penguins and his survival probability is 1/20 then the opposite spectrum is 19/20 (0.95) but if there are 2 penguins with a survival rate of root.05 then chances they both survive is root.05 * root.05 = .05.
without knowing the number of penguins we cannot determine the answer.

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

AVMachine

Joined: 03 May 2024

Last visit: 26 Aug 2025

Posts: 190

Own Kudos:

154

[1]

Given Kudos: 40

Posts: 190

Kudos: 154

[1]

01 Jul 2025, 06:59

Kudos

Bookmarks

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

P = probability that a penguin in a marine study group completes their annual migration
1-P = probability that a penguin in a marine study group doesn't complete their annual migration

1. Let's consider only one penguin: P = 0.05; 1 - P = 0.95

2. Let's consider only two penguins: P^2 = 0.05; P = 0.223; (1 - P)^2 = 0.60

Hence, Ans is E. Cannot be determined from the given information

Mardee

Joined: 22 Nov 2022

Last visit: 16 Oct 2025

Posts: 127

Own Kudos:

110

[1]

Given Kudos: 17

Products:

Posts: 127

Kudos: 110

[1]

01 Jul 2025, 07:01

Kudos

Bookmarks

The probability that all penguins in the group complete the migration is 0.05
Each penguin migrates independently with the same probability, call it p
Let’s assume the group has n penguins
The probability that all complete migration is => p^n = 0.05

So, from the equation we have an equation with 2 unknown variable p and n
Without knowing p or n, we cannot compute (1-p)^n which is the probability that no one completes migration

E. Cannot be determined from the given information

SumnerSCB

Joined: 27 Apr 2025

Last visit: 08 Sep 2025

Posts: 36

Own Kudos:

[1]

Posts: 36

Kudos: 22

[1]

01 Jul 2025, 07:10

Kudos

Bookmarks

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

Not 100% sure, but without having the number of penguins, it seems you are unable to find the probability, so E.

UfuomaOh

Joined: 14 Sep 2023

Last visit: 17 Nov 2025

Posts: 83

Own Kudos:

[1]

Given Kudos: 14

Products:

Posts: 83

Kudos: 50

[1]

01 Jul 2025, 07:30

Kudos

Bookmarks

The probability that all the penguins complete their migration =0.05

P^n=0.05

n = the number of penguins in the group.

p =probability that a single penguin completes the migration.

Since each penguin has the same probability of completing the migration, the probability that all n penguins complete the migration is

P^n=0.05

The probability that none of the penguins complete the migration is (1-p)^n.

Since the probability that one penguin completes the migration is unknown and the number of penguins, n is unknown.

Thus the probability cannot be determined and the answer is E

Raome

Joined: 21 Apr 2025

Last visit: 18 Nov 2025

Posts: 109

Own Kudos:

Given Kudos: 84

Location: India

Posts: 109

Kudos: 30

01 Jul 2025, 07:48

Kudos

Bookmarks

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more

P(no penguins complete migration)= 1 - P(allpenguins complete migration)
=1 - 0.05 = 0.95 (D)

monarchme

Joined: 13 Feb 2021

Last visit: 14 Oct 2025

Posts: 19

Own Kudos:

Given Kudos: 14

Posts: 19

Kudos: 28

01 Jul 2025, 08:04

Kudos

Bookmarks

Assuming every penguin has a p probability,and we have n groups so its p^n=0.05 but we do not know the value of p and n and hence the answer is E

gabiru97

Joined: 24 Feb 2022

Last visit: 18 Nov 2025

Posts: 18

Own Kudos:

Given Kudos: 4

Posts: 18

Kudos: 13

02 Jul 2025, 04:23

Kudos

Bookmarks

Probablity that non peguin complete migration "P(N)" may be best calculated as 1 - the probability that at least one penguin completes the migration "P(A)"

To find P(A), we must know the probability "p" of a single penguin to complete the migration and the number "n" of penguins, and we have none of those.

The information given only tells us that p^n = 0.05, but since we have neither p or n, this piece of info does not help us. Thus, it is not possible to determine what is asked

Bunuel

This question was provided by GMAT Club
for the GMAT Club Olympics Competition

Win over $30,000 in prizes such as Courses, Tests, Private Tutoring, and more