GRE Subject Test: Math : Algebra

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

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Example Questions

Example Question #171 : Algebra

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 #172 : Algebra

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 #173 : Algebra

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 #174 : Algebra

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.

Example Question #175 : Algebra

Perform the following operation.

  

Possible Answers:

Correct answer:

Explanation:

The first step to solving this operation is to do the multiplication:

  

Once we have multiplied the matrices, we can perform the addition portion:

Example Question #176 : Algebra

Perform the following operation.

Possible Answers:

Correct answer:

Explanation:

The first step is to solve whatever is in the parentheses, in this case it is addition: 

We then substitute our solution into the parentheses:

Our next, and final step in this problem, is to carry out the multiplication:

Example Question #177 : Algebra

Find the inverse of the following matrix, if possible. 

Possible Answers:

The inverse does not exist.

Correct answer:

Explanation:

Write the formula to find the inverse of a matrix.

Substituting in the given matrix we are able to find the inverse matrix.

Example Question #4 : Linear Algebra

Find the inverse of the following matrix, if possible. 

Possible Answers:

The inverse does not exist.

Correct answer:

Explanation:

Write the formula to find the inverse of a matrix.

Using the given information we are able to find the inverse matrix.

 

 

Example Question #1 : Inverse Functions

Find the inverse of the function.

 

Possible Answers:

Correct answer:

Explanation:

To find the inverse function, first replace  with :

Now replace each  with an  and each  with a :

Solve the above equation for :

Replace  with . This is the inverse function:

Example Question #3 : Find The Inverse Of A Relation

Find the inverse of the function .

Possible Answers:

Correct answer:

Explanation:

To find the inverse of , interchange the  and  terms and solve for .

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