

1. 
What interest rate is required for an investment with continuously compounded interest to double in 9 years? 


A. 
3.76% 
B. 
8.66% 


C. 
3.34% 
D. 
7.70% 


Hint 


2. 
Suppose the population in a city can be modeled by the equation y = 15,000(1.02)^{x}, where x is the number of years since 1950. Predict the population in 2010. 


A. 
49,215 
B. 
33,967 


C. 
5,486 
D. 
523,333 


Hint 


3. 
Find the amount of time needed for an investment to double at a rate of 7.1% if the interest is compounded continuously. 


A. 
4.3 years 
B. 
9.76 years 


C. 
11.2 years 
D. 
2.5 years 


Hint 


4. 
If the population of a city can be modeled by the equation y = 12,500(1.03) ^{x}, where x is the number of years since 1965, what is the estimated population in 2006? 


A. 
45,100 
B. 
38, 611 


C. 
41,999 
D. 
549,464 


Hint 


5. 
The number of bacteria in a culture can be modeled by the exponential function N = 6.5828(1.1769)^{t}, where t is the number of hours. What will the number of bacteria be in 19 hours? Round to nearest whole number. 


A. 
177 
B. 
121 


C. 
145 
D. 
203 


Hint 

