2. Questions Bank
  3. JEE Main & Advanced
  4. Mathematics
  5. Sequence & Series

JEE Main & Advanced Mathematics Sequence & Series Question Bank Mock Test - Sequences and Series

  • question_answer
    The 15th terms of the series \[2\frac{1}{2}+1\frac{7}{13}+1\frac{1}{9}+\frac{20}{23}+...\]is

    A) \[\frac{10}{39}\]                      

    B) \[\frac{10}{21}\]

    C) \[\frac{10}{23}\]                      

    D) none of these

    Correct Answer: A

    Solution :

    [a] Reciprocals of the terms of the series are 2/5, 13/20, 9/10, 23/20,...or 8/20, 13/20, 18/20, 23/30,..its nth term is \[\frac{8+(n-1)5}{20}=\frac{5n+3}{20}\] Therefore, the 15th term is \[\frac{20}{78}=\frac{10}{39}\].


You need to login to perform this action.
You will be redirected in 3 sec spinner