Question

An experiment succeeds twice as often as it fails. Find the probability that in the next six trials, there will be at least 4 successes.

Answer 1

The probability of success is twice the probability of failure. 

Let the probability of failure be x. 

∴ Probability of success = 2x

Let X be the random variable that represents the number of successes in six trials. 

By binomial distribution, we obtain