Which term of AP 3, 8, 13, 18, …….. is 78?

  1. A23
  2.  A19
  3.  A16
  4.  A22
Anurag Mishra Professor Asked on 18th April 2016 in No Category.
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  • 1 Answer(s)

    Answer: (3) A16 

    Solution:-
    Let the nth term be 78. 
    First term (a) = 3, 
    d = 8 – 3 
     = 5. 

    Formula-
    nth term = a + (n – 1) d

    Then, 
    3 + ( n – 1) 5 = 78
    3 + 5 n – 5 = 78 
    5 n = 78 + 2
    5 n = 80 
    n = 80/5
    n = 16 

    Then, 16th term will be 78. 

    Hence, the correct answer is option (3) A 16. 

    Anurag Mishra Professor Answered on 22nd April 2016.
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