How do i solve this and make sure that the answer is correct

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?

Find the roots of the polynomial function f(x) = x^3 + 2x^2 + x

Rose bought a new hat when she was on vacation. the following formula describes the percent sales tax rose paid b=t-c/c