I need help i dont know the answers

Find the midpoint m of z1=(8+5i) and z2=(12+3i)

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?

15. if the 8% tax on an item amounts to $0.96, what is the final price (tax included) of the item?