A corporation has 25 manufacturing plants. Of these, 18 are domestic and 7 are situated outside the United States. Each year performance evaluation is conducted for 4 randomly chosen plants.
a. Determine the probability that the evaluation will include no plants outside the country?
b. Determine the probability that the evaluation will include at leat 1 plant outside the country?
c. Determine the probability that the evaluation will include no more than 1 plant outside the country?