Mateo's Cafe offers two kinds of espresso: single-shot and double-shot. Yesterday afternoon, the cafe sold 80 espressos in all, 90% of which were single-shot. How many single-shot espressos did the cafe sell?

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?