At Ann's 7-years olds party all 20 invited guests are going to get some candy from the fish pond. In 12 of the bags there is an extra chocolate bar. Tina and James are first and second out, what is the probability that they both get a bag with an extra chocolate bar?
First, we calculate Tina's odds - we'll assume she's first. She has a 12 in 20 chance, so that's a 60% chance. Now, we figure out James' odds. If she took one with an extra bar, it would be 11 in 19, or 57.895%, and when we multiply that by the original 40%, we find there is a 34.737% chance of both peoplegetting one.