Kindred invested $38,976 into his first company. His investment decreased by 3.5% each year over the first 3 years. Which exponential decay model could Kindred use to determine the amount his investment will be worth if it continues to decrease at the same rate?

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?