GRE Subject Test: Math : Exponential Growth Applications

Study concepts, example questions & explanations for GRE Subject Test: Math

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Example Questions

Example Question #11 : Exponential Growth Applications

The rate of decrease of the number of concert attendees to former teen heartthrob Justice Beaver is proportional to the population. The population decreased by 34 percent between 2013 and 2015. What is the constant of proportionality?

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of growth of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value, and  is the constant of proportionality.

Since the population decreased by 34 percent between 2013 and 2015, we can solve for this constant of proportionality:

Example Question #16 : How To Find Constant Of Proportionality Of Rate

The rate of growth of the Land of Battlecraft players is proportional to the population. The population increased by 72 percent between February and October of 2015. What is the constant of proportionality?

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of growth of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value, and  is the constant of proportionality.

Since the population increased by 72 percent between February and October, we can solve for this constant of proportionality. It'll help to represent the months by their number in the year:

Example Question #31 : Exponential Functions

The rate of decrease of the gluten-eating demographic of the US is proportional to the population. The population decreased by 8 percent between 2014 and 2015. What is the constant of proportionality?

Possible Answers:

Correct answer:

Explanation:

We're told that the rate of growth of the population is proportional to the population itself, meaning that this problem deals with exponential growth/decay. The population can be modeled thusly:

Where  is an initial population value, and  is the constant of proportionality.

Since the population decreased by 8 percent between 2014 and 2015, we can solve for this constant of proportionality:

Example Question #351 : Gre Subject Test: Math

Bob invests  in a bank that compounds interest continuously at a rate of . How much money will Bob have in his account after  years? (Round answer to  decimal places.) 

Possible Answers:

Correct answer:

Explanation:

Step 1: Recall the formula for continuously compounded interest

The formula is: , where:

 is the Final balance after  years.

 is the original investment balance. 

 is the exponential function

 is the interest rate, usually written as a decimal

 is the time, usually in years

Step 2: Plug in all the information that we have into the formula

Simplify:

Step 3: Evaluate.

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