1. Records show that the probability that it rains in our town on a single day is 0.35. If rain on different days constitutes independent events, find the probability that it:
a. Rains on neither of two given days.
b. Rains on both of two given days.
c. Rains on exactly one of the two given days.
2. An eight-cylinder engine (8 spark plugs) has two spark plugs that need to be replaced.
a. If one spark plug is replaced randomly, what is the probability that one of the bad ones is replaced?
b. If two are replaced randomly, what is the probability that both bad ones are replaced?
3. A parts store sells both new and used parts. Sixty percent of the parts in stock are used. Sixty-one percent are used or defective. If 5% of the store's parts are defective, what percentage are both used and defective?