Results 1 to 3 of 3

Math Help - Should be simple...

  1. #1
    Newbie
    Joined
    Aug 2009
    Posts
    6

    Should be simple...

    ...but I'm afraid I can't recall how to answer such questions:

    'After taking 3 math quizzes Elise has an average of 89. What must she score on the fourth quiz to raise her average to 91?'

    Help is very much appreciated.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Aug 2009
    From
    Mumbai
    Posts
    83
    Let her scores in the first three quizzes be  x1 , x2 , x3 respectively.

    Given that (x1+x2+x3)/3 = 89

    so x1+x2+x3 = 267

    Now her average in four quizzes would be

    (x1+x2+x3+x4)/4

    x4 is her scr in the 4th quiz.

    since (x1+x2+x3+x4)/4=91

    x1+x2+x3+x4=91(4)=364

    so x4=364-(x1+x2+x3)

    Plug in the value of x1+x2+x3 from above and find x4

    x4=364-267=97
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Aug 2009
    Posts
    6
    Thanks very much!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Really simple question too hard for a simple mind
    Posted in the Statistics Forum
    Replies: 2
    Last Post: October 5th 2010, 08:03 AM
  2. Easy Question - Simple Interest, Simple Discount
    Posted in the Business Math Forum
    Replies: 0
    Last Post: September 21st 2010, 08:22 PM
  3. Replies: 4
    Last Post: May 4th 2010, 09:08 AM
  4. Simple Integral Question (I think it's simple)
    Posted in the Calculus Forum
    Replies: 7
    Last Post: February 13th 2010, 02:37 PM
  5. Replies: 2
    Last Post: November 12th 2009, 03:09 PM

Search Tags


/mathhelpforum @mathhelpforum