RAJASTHAN ­ PET Rajasthan PET Solved Paper-2003

  • question_answer
    If 5th term and 11th term of a harmonic progression are\[\frac{1}{45}\]and\[\frac{1}{69}\]respectively, then 16th term is

    A)  \[\frac{1}{89}\]

    B)  \[\frac{1}{85}\]

    C)  \[\frac{1}{81}\]

    D)  \[\frac{1}{77}\]

    Correct Answer: A

    Solution :

     Since, 5th and 11th terms of a harmonic progression are\[\frac{1}{45}\]and\[\frac{1}{69}\]respectively, therefore 5th and 11th terms of the corresponding AP are 45 and 69 respectively. \[\therefore \] \[45=a(5-1)d\] \[\Rightarrow \]       \[45=a+4d\]                   ...(i) and      \[69=a+10d\]                 ...(ii) On solving Eqs. (i) and (ii), we get \[a=29,d=4\] \[\therefore \] \[{{T}_{16}}=29+15\times 4=89\] \[\therefore \]16th term of harmonic progression\[=\frac{1}{89}\]


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