Question: 1. A box contains ninety good and ten defective screws. If ten screws are used, what is the probability that none is defective?
2. From the population of five symbols a, b, c, d, e, a sample of size 25 is taken. Find the probability that the sample will contain five symbols of each kind. Check the result in tables of random numbers,20 identifying the digits 0 and 1 with a, the digits 2 and 3 with b, etc.