Aircraft inspectors (who specialize in mechanical engineering) report wing cracks in aircraft as nonexistent, detectable (but still functional), or critical (needs immediate repair). For a particular model of commercial jet 10 years old, history indicates 75% of the planes had no wing cracks, 20% had detectable wing cracks, and 5% had critical wing cracks. Five planes that are 10 years old are randomly selected. What is the probability that

(a) 4 have no cracks, 1 has detectable cracks, and 0 have no critical cracks?

(b) 3 have no cracks, 1 has detectable cracks, and 1 has critical cracks?