(Unlimited Practice) SAT Math: Exponential Growth/Decay

1. A farm has 10,000 mango trees. How many trees will there be after 2 years if the tree count is decreasing at a rate of 1.5% annually. Round your answer to the nearest whole number.

9,697

9,702

9,687

9,692

2. A 24-year old office worker is offered an opportunity to invest some money for retirement that pays 9.5% annual interest compounded continuously. How much does the office worker needs to invest today to have $1,000,000 when he retires at the age of 65? Round the answer to the nearest dollar.

$\$24,231$

$\$24,211$

$\$24,216$

$\$24,236$

3. A tank is filled to the brim with 2,000 liters of water. The pump connected to the tank is turned on and draws out water at a constant rate. After 20 minutes, only 75% of water is left in the tank. Which of the following equations models the liters of water, $l$ , left in the tank $m$ minutes after the pump is turned on?

$l = 2,000-1500m$

$l = 2,000+150m$

$l = 2,000-25m$

$l = 2,000-500m$

4. A 30-year old office worker is offered an opportunity to invest some money for retirement that pays 3.5% annual interest compounded continuously. How much does the office worker needs to invest today to have $1,000,000 when he retires at the age of 65? Round the answer to the nearest dollar.

$\$299,982$

$\$299,997$

$\$300,002$

$\$299,977$

5. The population of zebras in a certain forest was found to be decreasing at a rate of 4.2% per year. If the population of zebras 3 years ago is 6,000, what will the population of zebras be after 5 years? Round the answer to the nearest whole number.

4,252

4,232

4,237

4,257