The travel times spent by a student from his home to La Salle or vice versa can be approximated as Normal distribution with a mean of 28 minutes and standard deviation of 3.5 minutes. If a student has his 1st period subject at 7:30 am and he leaves home to La Salle at 7:00 AM. What is the probability that he will be late for his 1st period subject? (round off answer to four decimal) What time should he leave home to La Salle so that he will be on time, 90% of the times for his 1st period subject? (answer must expressed as hour:minute, ex. 6:30)