JEE Main & Advanced JEE Main Paper (Held On 10 April 2015)

  • question_answer
    Let the sum of the first three terms of an A.P. be 39 and the sum of its last four terms be 178. If the first term of this A.P. is 10, then the median of the A.P. is : JEE Main Online Paper (Held On 10 April 2015)

    A)  28                                         

    B)  31

    C)  29.5                                      

    D)  26.5

    Correct Answer: C

    Solution :

                     \[{{a}_{1}}{{a}_{2}}{{a}_{3}}\] \[{{a}_{2}}=\frac{3a}{3}=13\]                      \[d=3\] sum of last four term = 178 \[{{a}_{n-3}}{{a}_{n-2}}{{a}_{n-1}}{{a}_{n}}\] Their mean \[=\frac{178}{4}=44.5\] \[{{a}_{n}}=44.5+1.5+3\] = 49 Median \[=\frac{10+49}{2}=\frac{59}{2}=29.5\]


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