GRE Math : How to find value with a number line

Study concepts, example questions & explanations for GRE Math

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Example Questions

Example Question #1 : Number Line

The range of the earnings for architecture graduates is , and the range of the salaries for engineering graduates is .

Which of the following statements individually provide(s) sufficient additional information to determine the range of the salaries of all graduates between the two professions?

A: The median salary for the engineers is  greater than that of the architects.

B: The average (arithmetic mean) of the engineers is  greater than that of the architects.

C: The lowest salary of the engineers is  less than the lowest of the architects.

Possible Answers:

B only

A and C only

C only

A only

A, B, and C

Correct answer:

C only

Explanation:

The provision of the bottom-end of the engineering range is the only additional information that provides us a fixed endpoint from which we can build off of by supplementing with the ranges provided in the question, to give us the full range between both engineering and achitecture graduates. See the diagram provided to understand how this can be done.

Gre6

 

Even if the mean and medians were provided, these additional values give us no information on the endpoints of the salaries, and the question only asks for the range. 

Example Question #2 : Number Line

What's the distance between  and  on a number line?

Possible Answers:

Correct answer:

Explanation:

Let's draw a number line. 

Q1

Since a number line is straight and contains the numbers consecutively, we just subtract  from  to get 

Example Question #3 : Number Line

Which of the following answer best fits in the picture below?

Q1

Possible Answers:

Correct answer:

Explanation:

Open circles mean the values are excluded from the set.

The number line shows the set is between  and  exclusive.

The only value in that set would be 

Example Question #4 : Number Line

If , then where on the number line lies ?

Possible Answers:

Correct answer:

Explanation:

Because a number line contains both positive and negative integers, we need to consider both possibilities. 

 is  and that value is the same as . Therefore we eliminate the  choice because  will always be greater than those values raised to the  power.

Next  is . We elminate both the positive and negative range of . If we look at the difference between  and , it's over .

Then, we should guess that  will definitely be greater than  so therefore answer is .

Remember, a negative value raised to an even power will always have a positive value. 

Example Question #5 : Number Line

If perimeter of equilateral triangle is , what is the height of the triangle?

Possible Answers:

Correct answer:

Explanation:

Since perimeter of equilateral triangle is  and we have three equal sides, we just divide that vaue by  to get . To find height, we can set-up a proportion. 

The height is opposite the angle . Side opposite  is  and the side of equilateral triangle which is opposite  is .

 Cross multiply.

 Divide both sides by 

 

Let's simplify by factoring out  to get a final answer of 

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