# Math Help - Calculating poisson distribution probabilities?

1. ## Calculating poisson distribution probabilities?

If X has a Poisson distribution such that 2P (X = 1) = P (X = 2), fi…nd P (X = 3)
What is the 2P bit about? Thank you for any help.

2. Originally Posted by Intsecxtanx
If X has a Poisson distribution such that 2P (X = 1) = P (X = 2), fi…nd P (X = 3)
What is the 2P bit about? Thank you for any help.
Write an equation that says that twice the probability that X = 1 is equal to the probability that X = 2. Use this equation to solve for the mean. Then calculate the required probability.