A firm has two computer systems available for processing telephone orders. At any given time, system A has a 10% chance of being "down," while system B has just a 5% chance of being "down." The computer systems operate independently. For a typical telephone order, determine the probability that
a. neither computer system will be operational.
b. both computer systems will be operational.
c. exactly one of the computer systems will be operational.
d. the order can be processed without delay.