Shortly after being put into service, some buses manufactured by a certain company have developed cracks on the underside of the main frame.  Suppose a particular city has 25 of these buses, and cracks have actually appeared in 8 of them.

a) In how many ways can a sample of 5 buses contain exactly 4 with variable cracks?  The book is showing me the answer of 1190.  I am lost on how they are concluding that..  If someone could help please it would be greatly appreciated.