Each sample of water has a 10% chance of containing a particular organic pollutant. Assume that the samples are independent with regard to the presence of the pollutant. Find the probability that in the next 18 samples, exactly 2 contains the pollutant.
(a) P(x≥≥4)
(b) P(x≤≤4).
(c) P(3≤≤x≤≤7)
