What is the answer plz x=-42-8y -18x=-4-8y

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?

You give a $4 tip for a meal that cost $22. approximately what percent of the bill was your tip?

What is the frequency of the sinusoidal graph?