8% of the students at jefferson middle school are absent because of illness. if there are 150 students in the school, how many are absent?

Ineed with number 17 i don’t get it at alll

You were told that the amount of time lapsed between consecutive trades on the new york stock exchange followed a normal distribution with a mean of 15 seconds. you were also told that the probability that the time lapsed between two consecutive trades to fall between 16 to 17 seconds was 13%. the probability that the time lapsed between two consecutive trades would fall below 13 seconds was 7%. what is the probability that the time lapsed between two consecutive trades will be between 14 and 15 seconds?

Another type of subtraction equation is 16-b=7. explain how you would sole this equation then solve it.