Suppose that after 10 years of service, 40% of computers have problems with motherboards (MB), 30% have problems with hard drives (HD), and 15% have problems with both MB and HD.
(a) Are the events A have problems with motherboards" and B have problems with hard drives independent? Why or why not?
(b) What is the probability that a 10-year old computer still has fully functioning MB and HD?