Question 455178
You and your 50 coworkers decide to play a game that consists of flipping a coin once for each coworker. 
if the flip of the coin for the particular coworker results in head, you will have to pay them $1. 
If it results in a tail, neither party has to pay anything.
------------------ 
Assume that the coin you are using is a fair coin (i.e. the probability of getting a head or a tail is equal to 0.5) 
the probability that you will not have to pay more than $18, but less than $30 
---------------------
Binomial problem with n = 50 and p = 1/2
P(19<= x <=30) = binomcdf(50,0.5,30)-binomcdf(50,0.5,18) 
= 0.9081
==============
Cheers,
Stan H.
==============