Can u help me out pls

Is a positive integer raised to a negative power always positive

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?

1: 4 if the wew 35 surfboards at the beach how many were short boards?