JEE Main & Advanced Mathematics Probability Question Bank Binomial distribution

  • question_answer
    A coin is tossed 3 times. The probability of obtaining at least two heads is or Three coins are tossed all together. The probability of getting at least two heads is                                      [MP PET 1995]

    A)                 \[\frac{1}{8}\]       

    B)                 \[\frac{3}{8}\]

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

    D)                 \[\frac{2}{3}\]

    Correct Answer: C

    Solution :

               Required probability \[={{\left( \frac{1}{2} \right)}^{3}}.{}^{3}{{C}_{2}}+{{\left( \frac{1}{2} \right)}^{3}}.{}^{3}{{C}_{3}}=\frac{4}{8}=\frac{1}{2}.\]                                 {Here at least two heads means two heads or three heads}.


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