If the sum of mean and variance of a binomial distribution for 5 trials is 1.8 , then probability of a success is

Step-by-step solution

We have n p+n p q=1.8 , where n=5 aligned & np (1+ q )=1.8 5 p [1+(1- p )]=1.8 & 5 p (2- p )=1.8 10 p -5 p ^2=1.8 i.e. & 5 p ^2-10 p +1.8=0 5 p ^2-9 p - p +1.8=0 & 5 p ( p -1.8)-1( p -1.8)=0 (5 p -1)( p -1.8)=0 & p = 1 5 , 1.8 but p 1 p = 1 5 =0.2 aligned