Last visit was: 23 Apr 2026, 03:24 It is currently 23 Apr 2026, 03:24
Close
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.
Close
Request Expert Reply
Confirm Cancel
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,773
Own Kudos:
Given Kudos: 105,853
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,773
Kudos: 810,735
 [12]
Kudos
Add Kudos
12
Bookmarks
Bookmark this Post
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,773
Own Kudos:
810,735
 [2]
Given Kudos: 105,853
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,773
Kudos: 810,735
 [2]
2
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
lfbstn24
Joined: 29 Jan 2023
Last visit: 27 Jun 2024
Posts: 2
Given Kudos: 45
Location: Brazil
GMAT Focus 1: 615 Q81 V82 DI79
GPA: 4
Products:
GMAT Focus 1: 615 Q81 V82 DI79
Posts: 2
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
adijain14
Joined: 01 Jul 2024
Last visit: 20 Apr 2026
Posts: 1
Posts: 1
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I think this is a high-quality question and I agree with explanation.
User avatar
mbaaccount1234
Joined: 11 Jan 2024
Last visit: 29 Oct 2025
Posts: 68
Own Kudos:
16
 [1]
Given Kudos: 104
Location: Brazil
GMAT Focus 1: 655 Q86 V83 DI78
GPA: 8/10
GMAT Focus 1: 655 Q86 V83 DI78
Posts: 68
Kudos: 16
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
This is a great question that’s helpful for learning and I like the solution - it’s helpful. there is a typo in que question "lease"
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,773
Own Kudos:
Given Kudos: 105,853
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,773
Kudos: 810,735
Kudos
Add Kudos
Bookmarks
Bookmark this Post
mbaaccount1234
This is a great question that’s helpful for learning and I like the solution - it’s helpful. there is a typo in que question "lease"

Thank you!

P.S. Edited the typo. Thank you!
User avatar
Rebaz
Joined: 14 Feb 2014
Last visit: 23 Apr 2026
Posts: 145
Own Kudos:
Given Kudos: 4,772
Posts: 145
Kudos: 38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel

I understand your explaination until The question asks to find minimum n such that 1−(5/7)^n > 1/2

But i have no idea how you go from the above to the next step 1/2> (5/7)^n? What happend with the one (1)?

Can you please clarify that?

Thanks in advance!
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,773
Own Kudos:
810,735
 [1]
Given Kudos: 105,853
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,773
Kudos: 810,735
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Rebaz
Bunuel

I understand your explaination until The question asks to find minimum n such that 1−(5/7)^n > 1/2

But i have no idea how you go from the above to the next step 1/2> (5/7)^n? What happend with the one (1)?

Can you please clarify that?

Thanks in advance!

Subtract 1 from both sides:

-(5/7)^n > -1/2

Now multiply both sides by -1, which flips the inequality:

(5/7)^n < 1/2
User avatar
Rebaz
Joined: 14 Feb 2014
Last visit: 23 Apr 2026
Posts: 145
Own Kudos:
Given Kudos: 4,772
Posts: 145
Kudos: 38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
@
Bunuel
Rebaz
Bunuel

I understand your explaination until The question asks to find minimum n such that 1−(5/7)^n > 1/2

But i have no idea how you go from the above to the next step 1/2> (5/7)^n? What happend with the one (1)?

Can you please clarify that?

Thanks in advance!

Subtract 1 from both sides:

-(5/7)^n > -1/2

Now multiply both sides by -1, which flips the inequality:

(5/7)^n < 1/2
Bunuel

Thank you, i get it now.

Another question,if you donot mind, that i forgot to ask.

Why do you raise the probability that non is born on Monday or Tuesday (which is 5/7) to (N), which is the number of people? Why is the number of people in this case(which is N) utilized as an exponent?

Thanks again!
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 23 Apr 2026
Posts: 109,773
Own Kudos:
Given Kudos: 105,853
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,773
Kudos: 810,735
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Rebaz
@
Bunuel
Rebaz
Bunuel

I understand your explaination until The question asks to find minimum n such that 1−(5/7)^n > 1/2

But i have no idea how you go from the above to the next step 1/2> (5/7)^n? What happend with the one (1)?

Can you please clarify that?

Thanks in advance!

Subtract 1 from both sides:

-(5/7)^n > -1/2

Now multiply both sides by -1, which flips the inequality:

(5/7)^n < 1/2
Bunuel

Thank you, i get it now.

Another question,if you donot mind, that i forgot to ask.

Why do you raise the probability that non is born on Monday or Tuesday (which is 5/7) to (N), which is the number of people? Why is the number of people in this case(which is N) utilized as an exponent?

Thanks again!

If one person is chosen, the chance he is not born on Monday or Tuesday is 5/7.
If two people are chosen, the chance both are not born on Monday or Tuesday is 5/7 * 5/7 = (5/7)^2.
If n people are chosen, the chance none of them is born on Monday or Tuesday is (5/7)^n.
That’s why we raise it to the power of n.
Moderators:
Math Expert
109773 posts
Founder
43154 posts