Write an exponential function to model the situation and find the value of the function for the given amount of time.
1. The cost of tuition of a college is $15,000 and is increasing at a rate of 8% per year; 4 years.
2. The value of a car is $18,000 and is depreciating at a rate of 12% per year; 10 years.
3. The amount (to the nearest hundredth) of a 10-mg dose of a certain antibiotic decreases in your bloodstream at a rate of 16% per hour; 4 hours.
4. The number of student-athletes at a high school is 300 and is increasing at a rate of 7.5% per year; 5 years.
5. Bismuth-214 has a half-life of approximately 20 minutes. Find the amount of Bismuth-214 left from a 30 gram sample after 1 hour.
6. Annual sales for a company are $149,000 and are increasing at a rate of 6% per year; 7 years.
7. The population of a small town is 1,600 and is increasing at a rate of 3.4% per year; 10 years.
8. Mendelevium-258 has a half-life of approximately 52 days. Find the amount of Mendelevium-258 left from a 44 gram sample after 156 days.
9. Membership of a local club grows at a rate of 7.8% every 6 months and currently has 30 members; 3 years.
10. The population of a town is 21,000 and is decreasing at a rate of 2.5% per year; 6 years.
11. The value of a book is $58 and decreases at a rate of 10% per year; 8 years.