PLS EXPLAIN THE ANS FOR Q.NO.6 OF MISC EXC IN Pg 583 of NCERT TXT BK? (I didn't understand the formula used for solving it in txtbk sol of topper)

In this question, the experiment is dichotomous in nature.

 

That is, in the race, the player can clear the hurdle or knock down the hurdle.

 

Therefore, this experiment can have only two outcomes and are called bernoulli trials.

 

Let 'p' be the probability of success and 'q' be the probability of failure such that p + q = 1.

 

 

In an experiment of n-Bernoulli trials, the probabilities of 0, 1, 2, ... ,n successes can be obtained as 1st, 2nd,...,(n+1)th terms in the binomial expansion of

This probability distribution is called binomial distribution.

 

This formula has been used in problem 6.

 

Also, since we need to find the probability the player will knock down fewer than 2 hurdles, we need to find P(x=0) + P(x=1)