In a school of 1200 pupils 45% are boys how many boys are there in the school

What is the average rate of change for this function for the interval from x=2 to x=4 ?

Which number produces a rationale number when multiplied by 1/5

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?