Fifteen (15 ) cell phones have just been received at an authorized service center. Five of these phones are Galaxy, five are Samsung and the other 5 are Apple phones. Suppose these phones are randomly allocated and selected in random order to be serviced by the center. Answer the following questions:

a. What is the probability that the all of the Samsung phones are among the first ten to be serviced?

b. What is the probability that after servicing ten of these phones, phones of only two of the three types remain to be serviced?

c. What is the probability that two phones of each type are among the first six serviced?