Sponsored Ad:
Results 1 to 4 of 4

Thread: Which of the following is equal to (2^k)(5^(k-1))?

  1. #1
    Eager!
    Join Date
    Sep 2008
    Location
    Los Angeles
    Posts
    39
    Rep Power
    6


    Good post? Yes | No

    Which of the following is equal to (2^k)(5^(k-1))?

    Sponsored Ad:
    A. 2(10^(k-1))
    B. 5(10^(k-1))
    C. 10^k
    D. 2(10^k)
    E. 10^(2k-1)

    Please show your steps.

    Official Answer in a few...

  2. #2
    An Urch Guru Pundit Swami Sage 12rk34's Avatar
    Join Date
    Jun 2008
    Location
    INDIA
    Posts
    1,200
    Rep Power
    11


    Good post? Yes | No

    Heart

    (2^k)(5^(k-1) = 2*{2^(k-1)}*{5^(k-1)}
    = 2*{(2*5)^(k-1)}
    = 2*{10^(k-1)}
    Hence A.

  3. #3
    Trying to make mom and pop proud
    Join Date
    Mar 2009
    Posts
    5
    Rep Power
    6


    Good post? Yes | No
    Quote Originally Posted by linfongyu View Post
    A. 2(10^(k-1))
    B. 5(10^(k-1))
    C. 10^k
    D. 2(10^k)
    E. 10^(2k-1)

    Please show your steps.

    Official Answer in a few...
    Hi Im a new user for this community. If there is something wrong please feel free to correct it.

    The correct answer is A.

    First: (2^k)(5^(k-1)) = (2^k)((5^k)/5^1)

    Second: You can further simplify the exponential expression to:
    ((2^k)(5^k))/5

    Third: ((2^k)(5^k)) can be simplified to ((2*5)^k) --> 10^k

    Forth: So the most simplified expression is (10^k)/5

    Fifth: Let's check at each choices and find out which one can be
    simplified as same as (10^k)/5

    Look at choice A: 2(10^(k-1))

    This expression can be simplifed as follows:

    2((10^k)/10^1)) --> 2(10^k))/10 --> (10^k)/5

    That is exactly the same as what we could simplify from the questions.

    So the answer is A

  4. #4
    GMAT TEST EXPERTS MBAchase's Avatar
    Join Date
    Nov 2008
    Posts
    380
    Rep Power
    7


    Good post? Yes | No
    answer is A
    2 * 2^(k-1) * 5(k-1)
    = 2 * (2*5)^(k-1)
    =2 * (10)^(k-1)

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. equal to 10*
    By effective_factor in forum GMAT Problem Solving
    Replies: 5
    Last Post: 02-21-2009, 12:21 PM
  2. Is x^2 equal to xy
    By MarsAlien in forum GMAT Data Sufficiency
    Replies: 12
    Last Post: 08-05-2008, 09:59 AM
  3. Is M not equal to N?
    By silvergator in forum GMAT Data Sufficiency
    Replies: 6
    Last Post: 11-29-2005, 04:05 AM
  4. If r does not equal to zero...
    By Stormgal in forum GMAT Math
    Replies: 2
    Last Post: 05-16-2005, 07:02 PM
  5. equal, equal to or the equivalent of ?
    By Taf in forum GMAT Sentence Correction
    Replies: 12
    Last Post: 02-22-2005, 05:16 PM

Bookmarks

Posting Permissions

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

SEO by vBSEO ©2010, Crawlability, Inc.