In an inventory process it was determined that out of 122 to

In an inventory process, it was determined that out of 122 toys, 21 were defective. What is the probability (in percentage form) that in a box with 56 toys, exactly 10 toys are defective?

Solution

Note that the probability of x successes out of n trials is          
          
P(x) = C(N-K, n-x) C(K, x) / C(N, n)          
          
where          
N = population size =    122      
K = number of successes in the population =    21      
n = sample size =    56      
x = number of successes in the sample =    10      
          
Thus,          
          
P(   10   ) =    0.186510662 [ANSWER]