Answer:
Step-by-step explanation:
The geometric distribution represents "the number of failures before you get a success in a series of Bernoulli trials. This discrete probability distribution is represented by the probability density function:"
Let X the random variable that measures the number os trials until the first success, we know that X follows this distribution:
In order to find the expected value E(1/X) we need to find this sum:

Lets consider the following series:
And let's assume that this series is a power series with b a number between (0,1). If we apply integration of this series we have this:
(a)
On the last step we assume that
and
, then the integral on the left part of equation (a) would be 1. And we have:

And for the next step we have:

And with this we have the requiered proof.
And since
we have that:
Answer:4months
Step-by-step explanation:
Slope for the function is -1/3.5.
20% of 100 is 20. divide that by 2 to get 20% of 50. 20/2 is 10. 20% of 50 is 10. There are 10 blue marbles.
Hope it helped :)
Ali