Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Question on # of possible rearrangements given conditions

  1. Aug 5, 2011 #1
    1. How many ways are there to rearrange the letters of INVESTIGATION given that the first letter is a V and the last letter is not a T?

    I get the first part, first letter being V cuts the # of combinations from 13! to 12!, but how do I handle the part about the last letter not being T? Most of what I have found online doesn't really relate to this particular issue.
     
  2. jcsd
  3. Aug 5, 2011 #2

    ehild

    User Avatar
    Homework Helper

    How many possibilities do you have for the last letter? And then before the last one?

    ehild
     
  4. Aug 5, 2011 #3

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    12! is the number of permutations in which we allow both T and non-T as the last letter. Can you count the number in which T *is* the last letter?

    RGV
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook