Frankie is planning to buy a new mp3 player for $90. each month he doubles the amount he saved the previous month. if he saves $3 the first month, in how many months will frankie have enough money to buy the mp3 player?

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.