The probability of guessing correctly at least 8 out of 10 answers on a true-false type examination is

In the examination , we have only two option True and False.

So, The probability of getting True is , p= 1/2

And, similarly, probability of getting False is, q=1/2

The total number of Answer in examination , n=10

The probability of guessing correctly at least 8 it means r=8,9,10

We know, probability distribution P(X=r)=ⁿC_r (p)^r q^n-r

P(X=r)=P(r=8)+P(r=9)+P(r=10)

= ¹⁰C₈¹⁰C₉ ¹⁰C₁₀

[45+10+1]

[

Hence, Probability is