Amean ogre stole 27 of your muffins. that was 3/5 of all of them! with how many did you start ?

Just tell me how to set up the equation.

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 scale factor between two circles is 2x/5y what is the ratio of their areas?