JEE Main & Advanced Mathematics Probability Question Bank Binomial distribution

  • question_answer
    A coin is tossed successively three times. The probability of getting exactly one head or 2 heads, is         [AISSE 1990]

    A)                 \[\frac{1}{4}\]       

    B)                 \[\frac{1}{2}\]

    C)                 \[\frac{3}{4}\]       

    D)                 None of these

    Correct Answer: C

    Solution :

               Required probability                 \[={}^{3}{{C}_{1}}{{\left( \frac{1}{2} \right)}^{1}}.{{\left( \frac{1}{2} \right)}^{2}}+{}^{3}{{C}_{2}}{{\left( \frac{1}{2} \right)}^{2}}.{{\left( \frac{1}{2} \right)}^{1}}=\frac{3}{8}+\frac{3}{8}=\frac{6}{8}=\frac{3}{4}\].


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