• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• Reach higher with Artificial Intelligence. Guaranteed
Now free for 30 days

Available with Beat the GMAT members only code

• Get 300+ Practice Questions

Available with Beat the GMAT members only code

• Award-winning private GMAT tutoring
Register now and save up to \$200

Available with Beat the GMAT members only code

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

AEMCE

Meek_21 Newbie | Next Rank: 10 Posts
Joined
24 Sep 2017
Posted:
1 messages

AEMCE

Sun Sep 24, 2017 9:14 pm
Find the sum of all even integers from 12 to 650

GMAT/MBA Expert

GMATGuruNY GMAT Instructor
Joined
25 May 2010
Posted:
14018 messages
Followed by:
1812 members
13060
GMAT Score:
790
Mon Sep 25, 2017 2:49 am
Meek_21 wrote:
Find the sum of all even integers from 12 to 650
For any EVENLY SPACED SET:
Number of terms = (biggest-smallest)/interval + 1, where the interval is the distance between successive terms.
Average = median = (biggest + smallest)/2.
Sum = (number of terms)(average).

Here, the interval between successive terms is 2.
Thus:
Number of terms = (650-12)/2 + 1 = 325 - 6 + 1 = 320.
Average = (650+12)/2 = 325 + 6 = 331.
Sum = 320*331 = 105920.

_________________
Mitch Hunt
GMAT Private Tutor
GMATGuruNY@gmail.com
If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon.
Available for tutoring in NYC and long-distance.

Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.
pannalal Junior | Next Rank: 30 Posts
Joined
20 Sep 2017
Posted:
22 messages
2
Sun Sep 24, 2017 11:49 pm
Find the sum of all even integers from 12 to 650

We can solve question in different ways. Below, I give two methods:

(1) Let us divide the number 12 and 650 by 2 as we want sum of even numbers. We get 6 to 325. We add these numbers and multiply by 2. Total numbers = 325-6+1 = 320. So,
Sum = 320*(6+325)/2*2 = 320*331 = 105920.

(2) Using Arithmetic Progression Sum.
Sum = n/2*{2a+(n-1)d} where n = 320, a = 12, d = 2.
= 320/2*(24 + 319x2) = 160*(24 + 638) = 160*662 = 105920.

Best Conversation Starters

1 lheiannie07 92 topics
2 Roland2rule 61 topics
3 ardz24 60 topics
4 LUANDATO 59 topics
5 M7MBA 50 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 Rich.C@EMPOWERgma...

EMPOWERgmat

138 posts
2 GMATGuruNY

The Princeton Review Teacher

131 posts
3 Brent@GMATPrepNow

GMAT Prep Now Teacher

122 posts
4 Jeff@TargetTestPrep

Target Test Prep

114 posts
5 Scott@TargetTestPrep

Target Test Prep

100 posts
See More Top Beat The GMAT Experts