A software engineer wants to move across the country from Vancouver to Montral to work. On different days, she mails a cover letter and resume to three different companies in Montral. Suppose a letter sent from Vancouver to Montral has a probability of 0.75 of reaching Montral within three (3) days. (a) What is the probability that exactly two (2) of the three (3) letters will reach Montral within three (3) days? (b) What is the probability that at least one (1) of the three (3) letters will reach Montral within three (3) days? (c) If the three (3) letters are mailed together at the same time and location, how does your conclusion in part (a) change?