Last visit was: 25 Apr 2026, 22:58 It is currently 25 Apr 2026, 22:58
Home
Messages
Tests
Schools
Events
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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
User avatar
GMATBusters
User avatar
GMAT Tutor
Joined: 27 Oct 2017
Last visit: 23 Apr 2026
Posts: 1,922
Own Kudos:
6,858
 [25]
Given Kudos: 241
WE:General Management (Education)
Expert
Expert reply
Posts: 1,922
Kudos: 6,858
 [25]
How many 7-digit numbers are having sum of digits ODD? 13 Oct 2018, 09:59
1
Kudos
Add Kudos
23
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

55% (hard)

Question Stats:

59% (01:45) correct 41% (02:27) wrong based on 207 sessions

History

Date
Time
Result
Not Attempted Yet
How many 7-digit numbers are having sum of digits ODD?

A) 3505000
B) 4350200
C) 4500000
D) 4520500
E) 5502000
ShowHide Answer
Official Answer
C
Most Helpful Reply
avatar
DEEPIKA29
avatar
Joined: 08 Oct 2018
Last visit: 21 Oct 2018
Posts: 4
Own Kudos:
21
 [10]
Given Kudos: 43
Posts: 4
Kudos: 21
 [10]
How many 7-digit numbers are having sum of digits ODD? 13 Oct 2018, 10:13
9
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
smallest 7 digit number=1000000
greatest=9999999.
total 7 digit number=9999999-1000000+1=90000000
So now out of 9000000,half have sum as odd and half has sum as even.So 4500000 are having sum as odd.
so C is the answer
General Discussion
User avatar
Gladiator59
User avatar
Joined: 16 Sep 2016
Last visit: 18 Mar 2026
Posts: 840
Own Kudos:
2,719
 [1]
Given Kudos: 271
Status:It always seems impossible until it's done.
GMAT 1: 740 Q50 V40
GMAT 2: 770 Q51 V42
Products:
My Reviews
GMAT 2: 770 Q51 V42
Posts: 840
Kudos: 2,719
 [1]
How many 7-digit numbers are having sum of digits ODD? 13 Oct 2018, 10:05
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
According to me the answer should be (C). Please find my solution attached.

Regards,
GLadi
Attachments

Q4_1 (2).jpeg
Q4_1 (2).jpeg [ 77.95 KiB | Viewed 4868 times ]

User avatar
baru
User avatar
Joined: 18 Jan 2018
Last visit: 02 Dec 2020
Posts: 202
Own Kudos:
312
Given Kudos: 72
Location: India
Concentration: General Management, Healthcare
Schools: ISB '21 Booth '22 IIMB
GPA: 3.87
WE:Design (Manufacturing)
Schools: ISB '21 Booth '22 IIMB
Posts: 202
Kudos: 312
How many 7-digit numbers are having sum of digits ODD? 13 Oct 2018, 10:13
Kudos
Add Kudos
Bookmarks
Bookmark this Post
How many 7-digit numbers are having sum of digits ODD?
A) 3505000
B) 4350200
C) 4500000
D) 4520500
E) 5502000
OA: C
a 7 digit number : _ _ _ _ _ _ 7th'
first digit : {1,2,3,4,5,6,7,8,9} - 9 values
2nd,3rd,4th,5th,6th : {0,1,2,3,4,5,6,7,8,9} - 10 values
the 7th digit takes set of { 1,3,5,7,9} - 5 values , all odd numbers

total no of values you can get with these : 9*(10^5)*5 = 4500000
User avatar
Archit3110
User avatar
Major Poster
Joined: 18 Aug 2017
Last visit: 25 Apr 2026
Posts: 8,630
Own Kudos:
5,190
Given Kudos: 243
Status:You learn more from failure than from success.
Location: India
Concentration: Sustainability, Marketing
GMAT Focus 1: 545 Q79 V79 DI73
GMAT Focus 2: 645 Q83 V82 DI81
GPA: 4
WE:Marketing (Energy)
Products:
GMAT Club Tests Forum Quiz
GMAT Focus 2: 645 Q83 V82 DI81
Posts: 8,630
Kudos: 5,190
How many 7-digit numbers are having sum of digits ODD? 13 Oct 2018, 10:21
Kudos
Add Kudos
Bookmarks
Bookmark this Post
How many 7-digit numbers are having sum of digits ODD?
A) 3505000
B) 4350200
C) 4500000
D) 4520500
E) 5502000
Answer B,C ,D &E: 5,9,7,3
User avatar
u1983
User avatar
Current Student
Joined: 24 Aug 2016
Last visit: 06 Jun 2021
Posts: 700
Own Kudos:
873
Given Kudos: 97
GMAT 1: 540 Q49 V16
GMAT 2: 680 Q49 V33
Products:
My Reviews
GMAT 2: 680 Q49 V33
Posts: 700
Kudos: 873
How many 7-digit numbers are having sum of digits ODD? Updated on: 13 Oct 2018, 12:04
Originally posted by u1983 on 13 Oct 2018, 10:22.
Last edited by u1983 on 13 Oct 2018, 12:04, edited 1 time in total.
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Total number of 7 digit integers 9999999-999999=9,000,000
Half of them have even sum and other odd sum.
( can ve verified in any consecutive series if even number of terms---
say... 11,12,13, 14 ===> 4 terms ....2 even sum & 2 odd sum
again 11,12,13......20 ==>10 terms ....5 even sum & 5 odd sum)
Hence, Odd sum = 9,000,000/2= 4,500,000
Ans C.
User avatar
swapnil611
User avatar
Joined: 15 May 2017
Last visit: 08 Apr 2021
Posts: 8
Own Kudos:
2
Given Kudos: 170
Posts: 8
Kudos: 2
How many 7-digit numbers are having sum of digits ODD? 13 Oct 2018, 11:01
Kudos
Add Kudos
Bookmarks
Bookmark this Post
total count of 7 digit number =9999999-1000000+1=9000000...so every alternate number in the set will have a sum even or odd,so half the 7 digit numbers would have odd sum hence 9000000/2=4500000.Hence answer C
User avatar
ArjunJag1328
User avatar
Joined: 24 Dec 2017
Last visit: 12 Jan 2025
Posts: 135
Own Kudos:
74
Given Kudos: 48
Location: India
Concentration: Strategy, Real Estate
Schools: Johnson '21
Schools: Johnson '21
Posts: 135
Kudos: 74
How many 7-digit numbers are having sum of digits ODD? 28 Oct 2018, 03:40
Kudos
Add Kudos
Bookmarks
Bookmark this Post
7 digit numbers are from 1000000 to 9999999.

First we need to find the total number of terms from 1000000 to 9999999.

(Last term - first term) +1 => (9999999 - 1000000) + 1 => 8999999 + 1 => 9000000

We know there are 5 odd integers and 5 even integers in every 10 numbers.

So we divide 9000000/2 = 4500000

Hence C
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,987
Own Kudos:
1,118
Posts: 38,987
Kudos: 1,118
How many 7-digit numbers are having sum of digits ODD? 06 Nov 2025, 10:24
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Automated notice from GMAT Club BumpBot:

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

This post was generated automatically.
Moderators:
Bunuel
Math Expert
109830 posts
Krunaal
Tuck School Moderator
852 posts