# Math Help - Binomial and geometric distribution

1. ## Binomial and geometric distribution

1. The random variable S can take values. 1,2,3... And has a geometric distribution. it is given that p(S=2)= 0.2244. Find the value of p(S=1), given that it is less than 0.5

2. A biologists is collecting data about fruit flies . he knows that one fruit fly in 10 has a striped body, and this property occurs at random in the population of fruit flies. She needs to collect one fruit fly with a striped body.

find the number of fruit flies she must collect to be 99.99% sure of obtaining one with a striped body.

3. It is known that 9% of the population belongs to blood group B. A hospital consultant visits patients in a hospital and determines their blood groups, stopping when ha has found one member of blood group B

(b) how many patients must he examine. To be 99.8% confident of finding at least one in blood group B?

sorry for too many questions stuck and need answers for my home work . thank you for your time in explaining.

2. ## Re: Binomial and geometric distribution

Originally Posted by mysur
1. The random variable S can take values. 1,2,3... And has a geometric distribution. it is given that p(S=2)= 0.2244. Find the value of p(S=1), given that it is less than 0.5
If $p$ is $\mathcal{P}(S=1)=p$ then $\mathcal{P}(S=2)=(1-p)p=0.2244$.

Solve for $p$.