Assuming the outcomes are all equally likely what is the pro

Assuming the outcomes are all equally likely, what is the probability that you will get exactly three heads when you toss a coin five times?

Solution

Binomial Distribution

PMF of B.D is = f ( k ) = ( n k ) p^k * ( 1- p) ^ n-k
Where   
k = number of successes in trials
n = is the number of independent trials
p = probability of success on each trial

P( X = 3 ) = ( 5 3 ) * ( 0.5^3) * ( 1 - 0.5 )^2
= 0.3125