6. The number of meteorites that hit the Earth follows a Poisson process with rate A = 200 per month. Each meteorite has prohabiht},r p of reaching the grolmd, otherwise it burns up in the air. Assume the usual independence when necessary. a. If 200 meteorites have hit the Earth in a particular month, what is the expected number of them that reached the ground? b. If in another particular month, 20 meteorites were found to have reached ground, what is the expected number of meteorites (including those burnt up in the air} to have hit the Earth in that month