Welcome! Check out our free B-School Guides to learn how you compare with other applicants.
Login or Register
 

Mean

This topic has 2 member replies
Bookmark
Previous Topic Next Topic
GmatKiss GMAT Titan Default Avatar
Joined
26 Jul 2011
Posted:
2790 messages
Followed by:
41 members
Thanked:
205 times
Target GMAT Score:
700+
GMAT Score:
640
Mean Post Sat May 05, 2012 6:20 am
Elapsed Time: 00:00
  • Lap #[LAPCOUNT] ([LAPTIME])
    The average (arithmetic mean) of the integers from 200 to 400, inclusive, is how much greater than the average of the integers from 50 to 100, inclusive?

    A.150
    B.175
    C.200
    D.225
    E.300

    Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!
    sam2304 GMAT Titan
    Joined
    26 Apr 2011
    Posted:
    1239 messages
    Followed by:
    25 members
    Thanked:
    228 times
    Test Date:
    26/06/2012
    Target GMAT Score:
    720
    GMAT Score:
    680
    Post Sat May 05, 2012 6:38 am
    GmatKiss wrote:
    The average (arithmetic mean) of the integers from 200 to 400, inclusive, is how much greater than the average of the integers from 50 to 100, inclusive?

    A.150
    B.175
    C.200
    D.225
    E.300
    Average of consecutive nos = sum of first and last number/2

    So for 200 to 400 = 200 + 400/2 = 300
    and 50 to 100 = 50 + 100/2 = 75

    Difference = 300 - 75 = 225

    IMO D.

    _________________
    Getting defeated is just a temporary notion, giving it up is what makes it permanent.
    http://gmatandbeyond.blogspot.in/

    aneesh.kg GMAT Destroyer!
    Joined
    16 Apr 2012
    Posted:
    382 messages
    Followed by:
    24 members
    Thanked:
    174 times
    Post Sat May 05, 2012 11:17 am
    The problem must've used the word 'consecutive'. Without it, the language is vague.

    Assuming the integers to be consecutive, it's an AP as well.

    Mean of an AP = Mean of the first and the last term = (first term + last term)/2
    (Do you know where this formula comes from?)

    Mean1 - Mean2
    =
    (200 + 400)/2 - (50 + 100)/2
    =
    300 - 75
    =
    225

    (D) is the answer.

    _________________
    Aneesh Bangia
    GMAT Math Coach
    aneesh.bangia@gmail.com

    GMATPad:
    Facebook Page: http://www.facebook.com/GMATPad

    Best Conversation Starters
    1 vipulgoyal 32 topics
    2 hemant_rajput 23 topics
    3 guerrero 18 topics
    4 abhirup1711 17 topics
    5 sana.noor 16 topics
    See More Top Beat The GMAT Members...

    Most Active Experts
    1 image description Brent@GMATPrepNow

    GMAT Prep Now Teacher

    		 211 posts
    2 image description GMATGuruNY

    The Princeton Review Teacher

    		 137 posts
    3 image description Jim@StratusPrep

    Stratus Prep

    		 60 posts
    4 image description Jon@Admissionado

    Admissionado

    		 49 posts
    5 image description David@VeritasPrep

    Veritas Prep

    		 31 posts
    See More Top Beat The GMAT Experts