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Find the last digit of 3^101 X 7^202

  1. Mar 20, 2015 #1
    1. The problem statement, all variables and given/known data
    find the last digit of 3^101 X 7^202

    2. Relevant equations


    3. The attempt at a solution
    i have cal. that the last digit is 7 by...:
    [147]mod10 X ([3^4]mod10)^25 X ([7^4]mod10)^25 = [7]mod10 X [1]mod10 = [7]mod10
    so the last digit is 7

    is it correct?
     
  2. jcsd
  3. Mar 20, 2015 #2

    Dick

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    Science Advisor
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    Yes.
     
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