SAT II Math I : Mathematical Relationships

Study concepts, example questions & explanations for SAT II Math I

varsity tutors app store varsity tutors android store

Example Questions

Example Question #4 : Indirect Proportionality

 varies directly with two times  and varies indirectly with three times . When  

  

and .

 

What is the value of  when  and  Round to the nearest tenth if needed.

Possible Answers:

Correct answer:

Explanation:

In order to solve for , first set up the variation equation for   and :

where  is the constant of variation. The  term varies indirectly with  and is therefore in the denominator.

Next, we solve for  based on the initial values of the variables:

Now that we have the value of , we can solve for  in the second scenario:

 

 

 

 

Example Question #5 : Indirect Proportionality

The number of slices of pizza you get varies indirectly with the total number of people in the restaurant. If you get  slices when there are  people, how many slices would you get if there are  people?

Possible Answers:

Correct answer:

Explanation:

The problem follows the formula 

 

where P is the number of slices you get, n is the number of people, and k is the constant of variation.

Setting P=3 and n = 16 yields k=48.

Now we substitute 12 in for n and solve for P

Therefore with 12 people, you get 4 slices.

Example Question #6 : Indirect Proportionality

The number of raffle tickets given for a contest varies indirectly with the total number of people in the building. If you get  tickets when there are  people, how many slices would you get if there are  people?

Possible Answers:

Correct answer:

Explanation:

The problem follows the formula 

 

where R is the number of raffle tickets you get, n is the number of people, and k is the constant of variation.

Setting R=20 and n = 150 yields k=3000.

Plugging in 100 for n and solving for R you get:

The answer R is 30 tickets.

Example Question #7 : Indirect Proportionality

 

The budget per committee varies indirectly with the total number of committees created. If each committee is allotted  when four committees are established, what would the budget per committee be if there were to be  committees?

 

Possible Answers:

Correct answer:

Explanation:

The problem follows the formula 

 

where B is the budget per committee, n is the number of committees, and k is the constant of variation.

Setting B=500 and n = 4 yields k=2000.

Now using the following equation we can plug in our n of 2 and solve for B.

The answer of B is $1000.

Example Question #8 : Indirect Proportionality

The number of hours needed for a contractor to finish a job varies indirectly with the total number of people the contractor hires. If the job is completed in  hours when there are  people, how many hours would it take if there were  people?

Possible Answers:

Correct answer:

Explanation:

The problem follows the formula 

 

where H is the number of hours to complete the job, n is the number of people hired, and k is the constant of variation.

Setting H=6 and n = 8 yields k=48.

Therefore using the following equation we can plug 16 in for n and solve for H.

Therefore H is 3 hours.

Example Question #9 : Indirect Proportionality

 varies inversely with . If  ,  . What is the value of  if  ? 

Possible Answers:

Correct answer:

Explanation:

 varies inversely with , so the variation equation can be written as:

 can be solved for, using the first scenario:

Using this value for  = 30 and  = 90, we can solve for :

Example Question #10 : Indirect Proportionality

 varies directly with  and inversely with the square root of . Find values for  and  that will give , for a constant of variation .  

Possible Answers:

 and 

 and 

 and 

All of these answers are correct

Correct answer:

All of these answers are correct

Explanation:

From the first sentence, we can write the equation of variation as:

We can then check each of the possible answer choices by substituting the values into the variation equation with the values given for  and .

 

Therefore the equation is true if  and 

 

Therefore the equation is true if  and 

 

Therefore the equation is true if  and 

The correct answer choice is then "All of these answers are correct" 

Example Question #31 : Basic Single Variable Algebra

 varies directly with  and . If  and , then . Find if  and

Possible Answers:

None of these answers are correct

Correct answer:

Explanation:

From the relationship of , , and ; the equation of variation can be written as:

Using the values given in the first scenario, we can solve for k:

Using the value of k and the values of y and z, we can solve for x:

Example Question #32 : Basic Single Variable Algebra

 varies inversely with  and the square root of . When  and . Find  when  and .

Possible Answers:

None of these answers are correct

Correct answer:

Explanation:

First, we can create an equation of variation from the the relationships given:

Next, we substitute the values given in the first scenario to solve for :

Using the value for , we can now use the second values for  and  to solve for :

Example Question #33 : Basic Single Variable Algebra

 varies directly with  and the square root of . If , and  then . Find the value of  if  and .

Possible Answers:

None of these answers are correct

Correct answer:

Explanation:

From the relationship given, we can set up the variation equation

Using the first relationship, we can then solve for 

Now using the values from the second relationship, we can solve for x

Learning Tools by Varsity Tutors