Lacoste middle school surveyed its student population about their favorite mobile
apps. the 786 students who listed facebook as their favorite app represented 32
fewer students than two times the number of students who listed instagram as their
favorite app. how many students listed instagram as their favorite app?

Among the most famous of all meteor showers are the perseids, which occur each year in early august. in some areas the frequency of visible perseids can be as high as 40 per hour. given that such sightings are poisson events, calculate the probability that an observer who has just seen a meteor will have to wait at least five minutes before seeing another.