Which of the following is true about the number 15? a it is a multiple of 5 and a factor of 25. b it is divisible by 3 and a factor of 45. c it is divisible by 6 and a multiple of 3. d it is divisible by 10 and a factor of 60.

The weekly amount spent by a company for travel has an approximately normal distribution with mean = $550 and standard deviation = $40. a) what is the probability that the actual weekly expense will exceed $570 for more than 20 weeks during the next year? (note: one year = 52 weeks) b) what is the probability that actual weekly expenses exceed $580 for 10 or more, but 16 or fewer weeks during the next year?