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    ​75013+750115+750135+…750199=?750 \frac13+750 \frac1{15}+750 \frac1{35}+…750 \frac1{99}=?75031​+750151​+750351​+…750991​=?​​
    Question

    75013+750115+750135+750199=?750 \frac13+750 \frac1{15}+750 \frac1{35}+…750 \frac1{99}=?​​

    A.

    750511750\frac{ 5}{11}​​

    B.

    75049750 \frac49​​

    C.

    750611750 \frac6{11}​​

    D.

    751511751 \frac5{11}​​

    Correct option is A

    Given:
    The series is 75013+750115+750135+...+750199 750\frac{1}{3} + 750\frac{1}{15} + 750\frac{1}{35} + ... + 750\frac{1}{99}​​
    Formula Used:
    Decomposition of mixed fractions: abc=a+bca\frac{b}{c} = a + \frac{b}{c}​​
    Telescoping series sum for terms of type 1n(n+2)=12(1n1n+2)\frac{1}{n(n+2)} = \frac{1}{2}(\frac{1}{n} - \frac{1}{n+2})​​
    Solution:
    750(13+115+135++199)750 \left(\frac{1}{3} + \frac{1}{15} + \frac{1}{35} + \ldots + \frac{1}{99}\right)​​

    =750(11×3+13×5+15×7++19×11)= 750 \left(\frac{1}{1 \times 3} + \frac{1}{3 \times 5} + \frac{1}{5 \times 7} + \ldots + \frac{1}{9 \times 11}\right)

    =750[12(113)+12(1315)+12(1517)++12(19111)]= 750 \left[\frac{1}{2}\left(1 - \frac{1}{3}\right) + \frac{1}{2}\left(\frac{1}{3} - \frac{1}{5}\right) + \frac{1}{2}\left(\frac{1}{5} - \frac{1}{7}\right) + \ldots + \frac{1}{2}\left(\frac{1}{9} - \frac{1}{11}\right)\right]

    =750×12(1111)= 750 \times \frac{1}{2}\left(1 - \frac{1}{11}\right)​​

    =750×12×1011= 750 \times \frac{1}{2} \times \frac{10}{11}​​

    =750×511= 750 \times \frac{5}{11}​​
    Final Answer
    So the correct answer is (a)

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