There are 7 performers who are to present their acts at a variety show. one of them insists on being the first act of the evening. if this request is granted, how many different ways are there to schedule the appearances?

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. according to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?