Does anyone know how to do this

On a piece of paper graph f(x)=5•(0.4)^x

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?

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?