JEE Main & Advanced Mathematics Sequence & Series Question Bank Arithmetic Progression

  • question_answer
    The sum of numbers from 250 to 1000 which are divisible by 3 is [RPET 1997]

    A) 135657

    B) 136557

    C) 161575

    D) 156375

    Correct Answer: D

    Solution :

    The number divisible by 3 between 250 to 1000 are 252, 255, .........., 999. \[\therefore \]\[{{T}_{n}}=999=252+(n-1)3\]\[\Rightarrow \]\[333=84+n-1\] \[\Rightarrow \]\[n=250\] \[\therefore \]\[S=\frac{n}{2}[a+l]=\frac{250}{2}[252+999]\] =\[125\times 1251=156375\].


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