Question

which of the contexts below could be modeled by an exponential function?
answer
a car depreciates at a rate of 3.3% per year.
an amusement park charges $4.00 to go on each of the rides.
a music service has a fixed monthly cost and charges $0.60 for each downloaded song.
snow was falling at a rate of 2.25 inches per hour.

Explanation:

Exponential functions model quantities that change by a constant percentage rate over time, not a constant absolute rate.

• Car depreciation at a fixed annual percentage rate fits this, as the value decreases by a proportion of its current value each year.
• The other options involve constant absolute rates (fixed per-ride cost, fixed per-song charge, fixed hourly snowfall), which are linear relationships.

Answer:

A car depreciates at a rate of 3.3% per year.