Last visit was: 24 Apr 2026, 03:02 It is currently 24 Apr 2026, 03:02
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
Sub 505 (Easy)|   Arithmetic|      
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 Apr 2026
Posts: 109,803
Own Kudos:
810,923
 [4]
Given Kudos: 105,868
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,803
Kudos: 810,923
 [4]
If S denotes the sum of the integers from 1 to 30, inclusive and t den 11 Dec 2018, 00:28
Kudos
Add Kudos
4
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
B
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

5% (low)

Question Stats:

86% (01:26) correct 14% (01:36) wrong based on 137 sessions

History

Date
Time
Result
Not Attempted Yet
If S denotes the sum of the integers from 1 to 30, inclusive and t denotes the sum of the integers from 31 to 60 inclusive. What is t-s?

A. 800
B. 900
C. 1000
D. 1100
E. 1200
ShowHide Answer
Official Answer
B
User avatar
Archit3110
User avatar
Major Poster
Joined: 18 Aug 2017
Last visit: 23 Apr 2026
Posts: 8,628
Own Kudos:
5,190
 [1]
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: 8,628
Kudos: 5,190
 [1]
If S denotes the sum of the integers from 1 to 30, inclusive and t den Updated on: 12 Dec 2018, 06:37
Originally posted by Archit3110 on 11 Dec 2018, 04:01.
Last edited by Archit3110 on 12 Dec 2018, 06:37, edited 1 time in total.
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
Bunuel
If S denotes the sum of the integers from 1 to 30, inclusive and t denotes the sum of the integers from 31 to 60 inclusive. What is t-s?

A. 800
B. 900
C. 1000
D. 1100
E. 1200
Show more


sn= n/2 ( 2a+(n-1)d)

1-30

30/2 ( 2*1+(29)*1)
= 465

similarly for 31-60
n= 60-31+1 = 30
so
30/2(2*31+29*1)

1365

difference 1365-465 = 900 IMO B
avatar
hibobotamuss
avatar
Joined: 28 Jun 2018
Last visit: 13 Oct 2019
Posts: 58
Own Kudos:
19
Given Kudos: 163
Posts: 58
Kudos: 19
If S denotes the sum of the integers from 1 to 30, inclusive and t den 12 Dec 2018, 05:55
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Archit3110 why have you taken A to be 30 and not 31 for the second calculation? Here: 30/2(2*30+29*1)
User avatar
Archit3110
User avatar
Major Poster
Joined: 18 Aug 2017
Last visit: 23 Apr 2026
Posts: 8,628
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: 8,628
Kudos: 5,190
If S denotes the sum of the integers from 1 to 30, inclusive and t den 12 Dec 2018, 06:00
Kudos
Add Kudos
Bookmarks
Bookmark this Post
hibobotamuss
Archit3110 why have you taken A to be 30 and not 31 for the second calculation? Here: 30/2(2*30+29*1)
Show more

No of digits would be (60-31) +1 : 30..

Posted from my mobile device
avatar
hibobotamuss
avatar
Joined: 28 Jun 2018
Last visit: 13 Oct 2019
Posts: 58
Own Kudos:
19
Given Kudos: 163
Posts: 58
Kudos: 19
If S denotes the sum of the integers from 1 to 30, inclusive and t den 12 Dec 2018, 06:02
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Archit3110 Yes but isnt a suppose to be the first term in the formula and not the number of terms?
avatar
hibobotamuss
avatar
Joined: 28 Jun 2018
Last visit: 13 Oct 2019
Posts: 58
Own Kudos:
19
Given Kudos: 163
Posts: 58
Kudos: 19
If S denotes the sum of the integers from 1 to 30, inclusive and t den 12 Dec 2018, 06:02
Kudos
Add Kudos
Bookmarks
Bookmark this Post
30/2(2*31+29*1) Shouldnt it be this?
User avatar
Gladiator59
User avatar
Joined: 16 Sep 2016
Last visit: 18 Mar 2026
Posts: 841
Own Kudos:
2,716
 [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: 841
Kudos: 2,716
 [1]
If S denotes the sum of the integers from 1 to 30, inclusive and t den 12 Dec 2018, 06:14
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Okay, one way to go about this is using big formulae for arithmetic progressions.

Let us see another way. :-D

t = 31+ 32 + ..+ 59 + 60
s = 1 + 2 + ... + 29 + 30

So t -s = (31 - 1) + ( 32 - 2) + ... + (59 - 29) + (60 - 30)
30 terms and each equals 30

Hence t - s = 30*30 = 900

Option (B) is our bet.

Best,
Gladi

Bunuel
If S denotes the sum of the integers from 1 to 30, inclusive and t denotes the sum of the integers from 31 to 60 inclusive. What is t-s?

A. 800
B. 900
C. 1000
D. 1100
E. 1200
Show more
User avatar
Archit3110
User avatar
Major Poster
Joined: 18 Aug 2017
Last visit: 23 Apr 2026
Posts: 8,628
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: 8,628
Kudos: 5,190
If S denotes the sum of the integers from 1 to 30, inclusive and t den 12 Dec 2018, 06:29
Kudos
Add Kudos
Bookmarks
Bookmark this Post
hibobotamuss
Archit3110 Yes but isnt a suppose to be the first term in the formula and not the number of terms?
Show more

Formula is
sn= n/2 ( 2a+(n-1)d)

a first term which, n no of terms and d is difference between in series amongst two no which should be same

Posted from my mobile device
avatar
hibobotamuss
avatar
Joined: 28 Jun 2018
Last visit: 13 Oct 2019
Posts: 58
Own Kudos:
19
Given Kudos: 163
Posts: 58
Kudos: 19
If S denotes the sum of the integers from 1 to 30, inclusive and t den 12 Dec 2018, 06:32
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Exactly, and here the first term is 31, so why have you taken it as 30?
User avatar
Archit3110
User avatar
Major Poster
Joined: 18 Aug 2017
Last visit: 23 Apr 2026
Posts: 8,628
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: 8,628
Kudos: 5,190
If S denotes the sum of the integers from 1 to 30, inclusive and t den 12 Dec 2018, 06:38
Kudos
Add Kudos
Bookmarks
Bookmark this Post
hibobotamuss
Exactly, and here the first term is 31, so why have you taken it as 30?
Show more

It was a typo .. edited ?
Total stays same so does the answer... ,

Posted from my mobile device
User avatar
kawal27
User avatar
Joined: 10 Oct 2019
Last visit: 15 Dec 2022
Posts: 81
Own Kudos:
442
Given Kudos: 82
Location: India
Schools: NTU '21
GMAT 1: 530 Q40 V23
Schools: NTU '21
GMAT 1: 530 Q40 V23
Posts: 81
Kudos: 442
If S denotes the sum of the integers from 1 to 30, inclusive and t den 30 Jun 2020, 05:13
Kudos
Add Kudos
Bookmarks
Bookmark this Post
set S = 1 to 30 total 30 terms n= number of terms a = first term l= last term
sum of AP= n/2 (a +l ) = 30/2 (1+30)=15*31=465
set T = 31 to 60 total 30 terms
sum of AP=n/2(a+l)=30/2 (31+60)=15*91=1365

T-S=1365-465=900

ANS : B
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,966
Own Kudos:
1,117
Posts: 38,966
Kudos: 1,117
If S denotes the sum of the integers from 1 to 30, inclusive and t den 11 Jun 2023, 02:07
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
109802 posts
Krunaal
Tuck School Moderator
853 posts