:( i dont know how to do this probability problem?
You have a tank full with 999885 blue balls and 115 red balls. You reach in and pick two out. What. Are the chances you will get 2 red, one red and one blue, or 2 red?
You have a tank full with 999885 blue balls and 115 red balls. You reach in and pick two out. What. Are the chances you will get 2 red, one red and one blue, or 2 red?
Comments
the total # of ball is a million, i.e. both red and blue
I assume there's no replacement. Then, we can use the hypergeometric distribution/formula:
(999885_C_y)*(115_C_(x-y)))/(1000000_C_x) [check wikipedia if the previous is unclear)
For the first task, we have ((999885_C_0)*(115_C_2))/(1000000_C_2), where C is for "choose" or combination, i.e. n!/(k!*(n-k)!)
The other tasks just changes the outputs.