JEE Main & Advanced JEE Main Paper (Held on 08-4-2019 Morning)

  • question_answer
    The sum of all natural numbers 'n' such that \[100<n<200\] and H.C.F. (91, n) > 1 is : [JEE Main 8-4-2019 Morning]

    A) 3221               

    B) 3121

    C) 3203               

    D) 3303

    Correct Answer: B

    Solution :

    \[{{S}_{A}}=\]sum of numbers between 100 & 200 which are divisible by 7. \[\Rightarrow \]\[{{S}_{A}}=105+112+....+196\] \[{{S}_{A}}=\frac{14}{2}[105+196]=2107\] \[{{S}_{B}}=\]Sum of numbers between 100 & 200 which are divisible by 13. \[{{S}_{B}}=104+117+....+195=\frac{8}{2}[104+195]=1196\]\[{{S}_{C}}=\]Sum of numbers between 100 & 200 which are divisible by both 7 & 13. \[{{S}_{C}}=182\] \[\Rightarrow \] \[H.C.F.\left( 91,n \right)>1={{S}_{A}}+{{S}_{B}}{{S}_{C}}=3121\]


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