JEE Main & Advanced Sample Paper JEE Main - Mock Test - 25

  • question_answer
    From a set of 40 cards numbered 1 to 40, 5 cards drawn at random and arranged in ascending order of magnitude \[{{x}_{1}}<{{x}_{2}}<{{x}_{3}}<{{x}_{4}}<{{x}_{5}}\]. The probability that \[{{x}_{3}}=24\] is

    A) \[\frac{^{16}{{C}_{2}}}{^{40}{{C}_{5}}}\] 

    B) \[\frac{^{23}{{C}_{2}}}{^{40}{{C}_{5}}}\]

    C) \[\frac{^{16}{{C}_{2}}{{\times }^{23}}{{C}_{2}}}{^{40}{{C}_{5}}}\]      

    D) None of these

    Correct Answer: C

    Solution :

    [c] : Five numbers can be drawn from 40 numbers in \[^{40}{{C}_{5}}\]ways, therefore total number of  cases\[{{=}^{40}}{{C}_{5}}\]. We want that \[{{x}_{3}}=24\]. \[\therefore \]The number of favourable cases are \[^{23}{{C}_{2}}{{\times }^{16}}{{C}_{2}}\] Hence, required probability \[=\frac{^{23}{{C}_{2}}{{\times }^{16}}{{C}_{2}}}{^{40}{{C}_{5}}}\]


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