Statistics And Probability Question 568

Question: One coin is thrown 100 times. The probability of coming tail in odd number

[MP PET 2004]

Options:

A) $ \frac{1}{2} $

B) $ \frac{1}{8} $

C) $ \frac{3}{8} $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

  •         Let p = Probability of getting tail =  $ \frac{1}{2} $                    q = Probability of getting head =  $ \frac{1}{2} $                    Also,  $ p+q=1 $  and  $ n=100 $                     
    

$ \therefore $ Required probability = $ P(X=1)+P(X=3)+…..+P(X=99) $ = $ ^{100}C_1p.q^{99}{{+}^{100}}C_3p^{3}q^{97}+……..{{+}^{100}}C_{99}p^{99}q^{1} $ = $ \frac{{{(p+q)}^{100}}-{{(p-q)}^{100}}}{2}=\frac{1}{2} $ .