Sponsored Ad:
See the top rated post in this thread. Click here

Results 1 to 5 of 5

Thread: 800 level Difficult Exponent question.

  1. #1
    Eager! Sumon1's Avatar
    Join Date
    Aug 2011
    Location
    Dhaka, Bangladesh
    Posts
    31
    Rep Power
    8


    Good post? Yes | No

    Exclamation 800 level Difficult Exponent question.

    Sponsored Ad:
    How can i solve this Data Sufficiency problem, anyone pull me out from the dark........
    If m is a positive integer, is the value p+q at least twice the value of 3m+4m ?

    1) p=3m+1 and q=22m+1
    2) m=4

  2. #2
    GRE-GMAT Instructor Brent Hanneson's Avatar
    Join Date
    Apr 2011
    Location
    Vancouver, Canada
    Posts
    362
    Rep Power
    10


    1 out of 1 members found this post helpful. Good post? Yes | No
    Quote Originally Posted by Sumon1 View Post
    How can i solve this Data Sufficiency problem, anyone pull me out from the dark........
    If m is a positive integer, is the value p+q at least twice the value of 3m+4m ?

    1) p=3m+1 and q=22m+1
    2) m=4
    First, let's rewrite the target question as "Is p+q > 2(3^m + 4^m) ?"

    Statement 1: If we replace p and q with their respective values, we can reword the target question as:
    Is 3^(m+1)+2^(2m+1) > 2(3^m + 4^m) ? (do we have sufficient information to answer this question? let's find out)

    To simplify the right-hand-side, first recognize that 4^m = (2^2)^m = 2^2m
    So, we can reword the target question as: Is 3^(m+1)+2^(2m+1) > 2(3^m + 2^2m) ?
    If we expand the right-hand-side, we get: Is 3^(m+1)+2^(2m+1) > (2)3^m + 2^(2m+1)?
    At this point, we can subtract 2^(2m+1) from both sides to get: Is 3^(m+1) > (2)3^m?
    Now, if we divide both sides by 3^m, we get: Is 3 > 2?
    Yes, 3 is greater than 2.
    Since we can answer the reworded target question with certainty, statement 1 is sufficient.

    Statement 2: Since we have no information about p and q, we cannot answer the target questions. So, statement 2 is not sufficient and the answer is
    SPOILER: A
    .

    Cheers,
    Brent

  3. #3
    Within my grasp!
    Join Date
    Aug 2011
    Location
    New Delhi, India
    Posts
    100
    Rep Power
    8


    Good post? Yes | No
    A it is.

    from (1) p + q = 3(m+1) + 2(2m+1) = 3m.3 + 4m.2 = 2(3m + 4m) + 3m
    since m is a positive integer, (1) is clearly suff.

    (2) tell us nothing abt p & q. So insuff.

  4. #4
    Within my grasp! sandeep_chads's Avatar
    Join Date
    Jan 2007
    Posts
    437
    Rep Power
    14


    Good post? Yes | No
    Thanks Brent - I got this question in MGMAT and was wondering there was something wrong with the question stem
    Hey Harvard, I am right here!!
    rep me if I made some sense

  5. #5
    An Urch Guru Pundit Swami Sage
    Join Date
    Aug 2007
    Posts
    696
    Rep Power
    14


    Good post? Yes | No
    Quote Originally Posted by Sumon1 View Post
    How can i solve this Data Sufficiency problem, anyone pull me out from the dark........
    If m is a positive integer, is the value p+q at least twice the value of 3m+4m ?

    1) p=3m+1 and q=22m+1
    2) m=4
    Obviously we need some help here, since we have no idea what p and q are.

    Part (1)
    p = 3^(m+1)
    q= 2^(2m+1)

    Now we know that p is a power of 3 greater than or equal to 9, and we know that q is an odd power of 2 greater than or equal to 8

    p+q = 3*3^m+2*2^(2m) = 3*3^m + 2*4^m > 2*3^m + 2*4^m

    SUFFICIENT

    Part (2)
    m = 4

    Again, we have no idea what p and q are, so we can safely say INSUFFICIENT

    A

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Unsolved problem solving question.....800 level.
    By Sumon1 in forum GMAT Problem Solving
    Replies: 2
    Last Post: 09-14-2011, 04:17 AM
  2. 800 level Difficult Combination problem
    By Sumon1 in forum GMAT Problem Solving
    Replies: 5
    Last Post: 09-13-2011, 10:52 AM
  3. Semicolon Confusion--700-800 Level Question
    By chaped in forum GMAT Sentence Correction
    Replies: 17
    Last Post: 10-07-2008, 02:10 AM
  4. Manhattan 700-800 level question
    By jcmsolis in forum GMAT Data Sufficiency
    Replies: 5
    Last Post: 11-02-2007, 08:04 PM
  5. Manhattan Hard Bin Question... (700-800 Level)
    By Prawler in forum GMAT Math
    Replies: 10
    Last Post: 09-29-2007, 04:42 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •