Last visit was: 09 Jul 2025, 12:53 It is currently 09 Jul 2025, 12:53
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
siddharthsinha123
Joined: 10 Jul 2016
Last visit: 01 Apr 2019
Posts: 32
Own Kudos:
218
 [26]
Given Kudos: 85
Products:
Posts: 32
Kudos: 218
 [26]
Kudos
Add Kudos
26
Bookmarks
Bookmark this Post
Most Helpful Reply
avatar
Mujeeb
Joined: 19 Oct 2015
Last visit: 26 Mar 2019
Posts: 17
Own Kudos:
18
 [14]
Given Kudos: 9
Posts: 17
Kudos: 18
 [14]
9
Kudos
Add Kudos
5
Bookmarks
Bookmark this Post
avatar
tapabrata
Joined: 11 Aug 2016
Last visit: 31 Jan 2018
Posts: 38
Own Kudos:
41
 [6]
Location: India
Concentration: Operations, General Management
GMAT 1: 710 Q49 V38
GPA: 3.95
WE:Design (Manufacturing)
GMAT 1: 710 Q49 V38
Posts: 38
Kudos: 41
 [6]
4
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
General Discussion
avatar
LarryM
Joined: 12 Sep 2016
Last visit: 24 Sep 2024
Posts: 15
Own Kudos:
Given Kudos: 6
Posts: 15
Kudos: 11
Kudos
Add Kudos
Bookmarks
Bookmark this Post
What is this question trying to ask? Could you please throw some light on it? It is ambiguous
avatar
goodie
Joined: 19 Jan 2017
Last visit: 29 Sep 2018
Posts: 4
Own Kudos:
5
 [2]
Given Kudos: 206
Posts: 4
Kudos: 5
 [2]
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
siddharthsinha123
Pat took 'N' whole days to complete the project. If the dash represents the digit which has been omitted, then which of the following could be the project?

a) 6_98
b) 6_36
c) 6_50
d) 6_90
e) 8_62

Question seems incomplete to me. I think 4 digit number with missing digit should represent total # of hours spent on the project. At least in this case it has some sense.

1 day = 24 hours = 8*3. Number should be divisible by 8 (and 4 as a result). Only option that fits is b.

May be somebody has better insight.
User avatar
siddharthsinha123
Joined: 10 Jul 2016
Last visit: 01 Apr 2019
Posts: 32
Own Kudos:
218
 [1]
Given Kudos: 85
Products:
Posts: 32
Kudos: 218
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
LarryM
What is this question trying to ask? Could you please throw some light on it? It is ambiguous


My apologies. The question has been edited.
User avatar
siddharthsinha123
Joined: 10 Jul 2016
Last visit: 01 Apr 2019
Posts: 32
Own Kudos:
218
 [2]
Given Kudos: 85
Products:
Posts: 32
Kudos: 218
 [2]
Kudos
Add Kudos
Bookmarks
Bookmark this Post
goodie
siddharthsinha123
Pat took 'N' whole days to complete the project. If the dash represents the digit which has been omitted, then which of the following could be the project?

a) 6_98
b) 6_36
c) 6_50
d) 6_90
e) 8_62

Question seems incomplete to me. I think 4 digit number with missing digit should represent total # of hours spent on the project. At least in this case it has some sense.

1 day = 24 hours = 8*3. Number should be divisible by 8 (and 4 as a result). Only option that fits is b.

May be somebody has better insight.

My apologies. The question has been edited.

The answer given by you is correct.
User avatar
IdiomSavant
Joined: 14 Sep 2016
Last visit: 03 May 2018
Posts: 45
Own Kudos:
45
 [1]
Given Kudos: 119
Concentration: Finance, Economics
Posts: 45
Kudos: 45
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
I brute forced it.

24X100=2400

2400
4800
7200

7200-240 = 6960 - 24 = 6936
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 09 Jul 2025
Posts: 21,066
Own Kudos:
26,121
 [1]
Given Kudos: 296
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 21,066
Kudos: 26,121
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
siddharthsinha123
Pat took 'N' whole days to complete the project. If the dash represents the digit which has been omitted, then which of the following could be the number of hours that he took to complete the project?

a) 6_98
b) 6_36
c) 6_50
d) 6_90
e) 8_62


Since there are 24 hours in a day, the number needs to be divisible by 24. Any number divisible by 24 must also be divisible by 4. A number is divisible by 4 when the last two digits of that number are divisible by 4. Since 36/4 = integer, 6_36 is the correct answer.

Answer: B
User avatar
goaltop30mba
Joined: 04 Dec 2015
Last visit: 08 Jul 2025
Posts: 186
Own Kudos:
Given Kudos: 406
Posts: 186
Kudos: 67
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ScottTargetTestPrep
siddharthsinha123
Pat took 'N' whole days to complete the project. If the dash represents the digit which has been omitted, then which of the following could be the number of hours that he took to complete the project?

a) 6_98
b) 6_36
c) 6_50
d) 6_90
e) 8_62


Since there are 24 hours in a day, the number needs to be divisible by 24. Any number divisible by 24 must also be divisible by 4. A number is divisible by 4 when the last two digits of that number are divisible by 4. Since 36/4 = integer, 6_36 is the correct answer.

Answer: B

how do we know that any number divisible by 24 must also be divisible by 4 ? could you explain a bit more??
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 09 Jul 2025
Posts: 21,066
Own Kudos:
26,121
 [1]
Given Kudos: 296
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 21,066
Kudos: 26,121
 [1]
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
aditliverpoolfc
ScottTargetTestPrep
siddharthsinha123
Pat took 'N' whole days to complete the project. If the dash represents the digit which has been omitted, then which of the following could be the number of hours that he took to complete the project?

a) 6_98
b) 6_36
c) 6_50
d) 6_90
e) 8_62


Since there are 24 hours in a day, the number needs to be divisible by 24. Any number divisible by 24 must also be divisible by 4. A number is divisible by 4 when the last two digits of that number are divisible by 4. Since 36/4 = integer, 6_36 is the correct answer.

Answer: B

how do we know that any number divisible by 24 must also be divisible by 4 ? could you explain a bit more??

Well 4 is a factor of 24 right? In other words 24 is a MULTIPLE OF 4. Thus, any number that is a multiple of 24 (or divisible by 24) is also divisible by 4.

For instance, 24, 48, 72, 96.... are all divisible by 24 and also by 4 right?
avatar
krishnakumarnri
Joined: 10 Nov 2018
Last visit: 18 Sep 2022
Posts: 1
Given Kudos: 13
Posts: 1
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
How did you limit it to 4 as against others factors such as 2,6 etc.. ?

Posted from my mobile device
User avatar
dracarys007
Joined: 04 Jun 2020
Last visit: 24 Feb 2022
Posts: 68
Own Kudos:
Given Kudos: 16
Location: India
Concentration: Strategy, General Management
GPA: 3.4
WE:Engineering (Consulting)
Kudos
Add Kudos
Bookmarks
Bookmark this Post
tapabrata
siddharthsinha123
Pat took 'N' whole days to complete the project. If the dash represents the digit which has been omitted, then which of the following could be the number of hours that he took to complete the project?

a) 6_98
b) 6_36
c) 6_50
d) 6_90
e) 8_62

Total number of hours = N*24

So the total number of hours has to be a multiple of 24. To find out if the number of hours is divisible by 24, we need to know all the digits. However the question stem says which of the values could be the number of hours so we need to eliminate answer choices based on the information we have.

We know that the number is divisible by 24, hence the number should be divisible by 4.

To find if the number is divisible by 4, we only need to check if the number formed by the last 2 digits is divisible by 4. We do not need the missing digit to know if the number is divisible by 4. All the options have the last 2 digits so we can check the divisibility by 4.
a) number formed by last 2 digits = 98 . Not divisible by 4
b) number formed by last 2 digits = 36 . Divisible by 4
c) number formed by last 2 digits = 50 . Not divisible by 4
d) number formed by last 2 digits = 90 . Not divisible by 4
e) number formed by last 2 digits = 62 . Not divisible by 4

Hence we can see that whatever the missing digit may be, options a,c,d and e will never be divisible by 4 and hence also not divisible by 24.

Answer is B.

Incorrect explanation. I do not agree. THe complete bnumber ahould be divisible by 8.
User avatar
yashikaaggarwal
User avatar
Senior Moderator - Masters Forum
Joined: 19 Jan 2020
Last visit: 30 Jun 2025
Posts: 3,095
Own Kudos:
3,034
 [1]
Given Kudos: 1,510
Location: India
GPA: 4
WE:Analyst (Internet and New Media)
Posts: 3,095
Kudos: 3,034
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
dracarys007
tapabrata
siddharthsinha123
Pat took 'N' whole days to complete the project. If the dash represents the digit which has been omitted, then which of the following could be the number of hours that he took to complete the project?

a) 6_98
b) 6_36
c) 6_50
d) 6_90
e) 8_62

Total number of hours = N*24

So the total number of hours has to be a multiple of 24. To find out if the number of hours is divisible by 24, we need to know all the digits. However the question stem says which of the values could be the number of hours so we need to eliminate answer choices based on the information we have.

We know that the number is divisible by 24, hence the number should be divisible by 4.

To find if the number is divisible by 4, we only need to check if the number formed by the last 2 digits is divisible by 4. We do not need the missing digit to know if the number is divisible by 4. All the options have the last 2 digits so we can check the divisibility by 4.
a) number formed by last 2 digits = 98 . Not divisible by 4
b) number formed by last 2 digits = 36 . Divisible by 4
c) number formed by last 2 digits = 50 . Not divisible by 4
d) number formed by last 2 digits = 90 . Not divisible by 4
e) number formed by last 2 digits = 62 . Not divisible by 4

Hence we can see that whatever the missing digit may be, options a,c,d and e will never be divisible by 4 and hence also not divisible by 24.

Answer is B.

Incorrect explanation. I do not agree. THe complete bnumber ahould be divisible by 8.
I don't think it has to do with divisibility rule. The number has to be divisible by 3 as well not just 8,
But if we see the question in the light of tens digit of 24 multiples.
24*N (any integer = n)
We will never find any number N which when multiplied with 24 leaves 98,90,50 or 62 as tens and ones digit combination

You can check by putting values in _ 6000 and 9000 is divisible by 24
We just have to check for 3 digit number which are divisible by 24. And there are only 37 such digits. Or you can use cyclicity of 4, which is the unit digit of 24 and has same multiplication and divisible concept as 24
We considered 4 because of same reason, not because it's a factor of 24

Posted from my mobile device
User avatar
Kinshook
User avatar
Major Poster
Joined: 03 Jun 2019
Last visit: 09 Jul 2025
Posts: 5,680
Own Kudos:
Given Kudos: 161
Location: India
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Products:
GMAT 1: 690 Q50 V34
Posts: 5,680
Kudos: 5,191
Kudos
Add Kudos
Bookmarks
Bookmark this Post
siddharthsinha123
Pat took 'N' whole days to complete the project. If the dash represents the digit which has been omitted, then which of the following could be the number of hours that he took to complete the project?

a) 6_98
b) 6_36
c) 6_50
d) 6_90
e) 8_62

Given: Pat took 'N' whole days to complete the project.
Asked: If the dash represents the digit which has been omitted, then which of the following could be the number of hours that he took to complete the project?

Number of hours = Number of days * 24 = 24k ; where k is an integer

24*250 = 6000
24k = {24,48,72,96,120,144,168,192,240,264,288,312,336,...}
6336 is could be number of hours Pat took to complete the project.

IMO B
User avatar
chrtpmdr
User avatar
Current Student
Joined: 24 Jul 2019
Last visit: 05 Oct 2022
Posts: 203
Own Kudos:
Given Kudos: 161
GMAT 1: 730 Q46 V45
GPA: 3.9
GMAT 1: 730 Q46 V45
Posts: 203
Kudos: 469
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Mujeeb
Pat took N whole Days
That means N(x)
1 Day= 24 hours

so x=24
24(N)--> Whatever the answers is , it should be multiple of 24.
As per cyclicity method --> 4 has cyclicity (4&6)

So 6_36 is answer (as its ends with 6)

Is that explanation really correct? ScottTargetTestPrep
I don't get why we should apply the cyclicity method.

For instance, 24*3 = 72 which is also a multiple by 24 and ends with a digit of 2, same applies to 24*17 = 408 ending in 8 and is still obviously a multiple of 24.
What the user above suggests, correct me if I am wrong, is seeking for a number which only consists of powers of 24 so -> 24^1, 24^2, 24^3 ... etc.
Is that really right?
User avatar
Fdambro294
Joined: 10 Jul 2019
Last visit: 06 Apr 2025
Posts: 1,353
Own Kudos:
Given Kudos: 1,658
Posts: 1,353
Kudos: 705
Kudos
Add Kudos
Bookmarks
Bookmark this Post
1 Day = 24 hours

If he completed N Whole Days, then N must be an Integer

Therefore, when we convert the N Days into Hours:

N Days * 24 hours / 1 Day = 24 * N

The Answer Choice must be a Multiple of 24


Rule 1: in order for an Answer Choice Number to be Divisible by 24, it must also be Divisible by the Factors of 24 - such as 4.

Rule 2: Divisibility Rule for any (2)^N Power ---- check whether the LAST N Digits of the Number are Divisible by (2)^N

4 = (2)^2 ----- Check whether the Last 2 Digits of Each Answer Choice is Divisible by 4

Using the Divisibility Rule for 4: only the LAST 2 Digits of Answer Choice B are Divisible by 4

Only -B- could represent a Whole Integer Number of N Days represented as Hours
avatar
DexterZabula
Joined: 25 Jul 2020
Last visit: 07 Feb 2021
Posts: 40
Own Kudos:
Given Kudos: 109
Posts: 40
Kudos: 17
Kudos
Add Kudos
Bookmarks
Bookmark this Post
siddharthsinha123
Pat took 'N' whole days to complete the project. If the dash represents the digit which has been omitted, then which of the following could be the number of hours that he took to complete the project?

a) 6_98
b) 6_36
c) 6_50
d) 6_90
e) 8_62


Just attempted this question. I did it as follows:

24x1 = 24
24x2 = 48
24x3 = 72
24x4 = 96
24x5 = 120
24x6 = 144
24x7 = 168
24x8 = 192
24x9 = 216
24x10 = 240

So, you can NOT have:
1. Even number at tenth place, if unit digit is 0 - C and D eliminated
2. Even number at tenth place, if unit digit is 2 - E eliminated
3. Odd number at tenth place, if unit digit is 8 - A eliminated

But you can have,
Odd number at tenth place, if unit digit is 6 - B opted.

Saved a lot of time.

Hope it helps.
Cheers :exclamation
User avatar
CrackverbalGMAT
User avatar
Major Poster
Joined: 03 Oct 2013
Last visit: 09 Jul 2025
Posts: 4,847
Own Kudos:
Given Kudos: 225
Affiliations: CrackVerbal
Location: India
Expert
Expert reply
Posts: 4,847
Kudos: 8,622
Kudos
Add Kudos
Bookmarks
Bookmark this Post
There are 24 hours in a day and Pat took N full days to complete the project. So, the total no of hours = N * 24.
Since No of hours is a multiple of 24, It should be divisible by 24.
24 = 8* 3.
So, we can say that , no of hours should be divisible by 8 as well as 3.

Divisibility rule of 8: Last 3 digit should be divisible by 8
Divisibility rule of 3: Sum of the digits should be divisible by 3

Since one digit is missing, we cannot apply divisibility rule of 8 and 3. But since its divisible by 8, we can say that it should be divisible by 4 as well.
Divisibility rule of 4 says last 2 digit of the number should be divisible by 4.

Let’s check the last two digit of the options and try to eliminate the options
a) 98 is not divisible by 4, Hence eliminated
b) 36 is divisible by 4, so it’s a possible answer
c) 50 is not divisible by 4, Hence eliminated
d) 90 is not divisible by 4, Hence eliminated
e) 62 is not divisible by 4, Hence eliminated

So Option C would be the correct answer.
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 37,364
Own Kudos:
Posts: 37,364
Kudos: 1,010
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Moderators:
Math Expert
102609 posts
PS Forum Moderator
682 posts