True or False If the time to wait for a selfserve check out

True or False: \"If the time to wait for a self-serve check out station at a grocery store has a uniform distribution from 0 to 10 minutes, then the probability that two randomly selected customers will both have to wait at least 7 minutes is 0.30.\"

Solution

FALSE. [ANSWER]

***********

0.30 is actually the probability for ONE customer to have 7 minutes or more.

Note that here,          
          
a = lower fence of the distribution =    0      
b = upper fence of the distribution =    10      
          
          
Note that P(x>c) = P(c<x<b) = (b-c)/(b-a). Thus, as          
          
c = critical value =    7      
          
Then          
          
P(x>c) =    0.3