Please help !! Don’t understand

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?

Create a data set with 8 points in it that has a mean of approximately 10 and a standard deviation of approximately 1.

X+ y = 5 ; x - y =3 solve using linear combination