GMAT Math : Problem-Solving Questions

Study concepts, example questions & explanations for GMAT Math

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Example Questions

Example Question #2 : Calculating Arithmetic Mean

Sandra's grade in economics depends on seven tests - five hourly tests, a midterm, and a final exam. The midterm counts twice as much as an hourly test; the final, three times as much.

Sandra's grades on the five hourly tests are 84, 86, 76, 89, and 93; her grade on the midterm was 72. What score out of 100 must she achieve on the final exam so that her average score at the end of the term is at least 80?

Possible Answers:

She cannot achieve this average this term

Correct answer:

Explanation:

This is a weighted mean, with the hourly tests assigned a weight of 1, the midterm assigned a weight of 2, and the final assigned a weight of 3. The total of the weights will be

 .

If we let  be Sandra's final exam score, Sandra's final weighted average will be

For Sandra to get a final average of 80, then we set the above equal to 80 and calculate :

Example Question #11 : Calculating Arithmetic Mean

Consider the following set of numbers:

85, 87, 87, 82, 89

What is the mean?

Possible Answers:

Correct answer:

Explanation:

Example Question #22 : Descriptive Statistics

Consider the following set of numbers:

85, 87, 87, 82, 89

What is the median?

Possible Answers:

Correct answer:

Explanation:

Reorder the values in numerical order:82, 85, 87, 87, 89

The median is the center number, 87.

Example Question #12 : Calculating Arithmetic Mean

Find the mean of the sample data set.

Possible Answers:

 

Correct answer:

Explanation:

The mean of a sample data set is the sum of all of the values divided by the total number of values. In this case:

Example Question #2031 : Problem Solving Questions

The average of the following 6 digits is 75. What is a possible value of ?

80, 78, 78, 70, 71,

Possible Answers:

Correct answer:

Explanation:

Therefore, the sum of all 6 digits must equal 450.

Subtract 377 from both sides.

Example Question #13 : Calculating Arithmetic Mean

When assigning a score for the term, a professor takes the mean of all of a student's test scores except for his or her lowest score.

On the first five exams, Donna has achieved the following scores: 76, 84, 80, 65, 91. There is one more exam in the course. Assuming that 100 is the maximum possible score, what is the range of possible final averages she can achieve (nearest tenth, if applicable)?

Possible Answers:

Minimum 66; maximum 99.2

Minimum 79.2; maximum 99.2

Minimum 80, maximum 84

Minimum 66; maximum 71.8

Minimum 79.2; maximum 86.2

Correct answer:

Minimum 79.2; maximum 86.2

Explanation:

The worst-case scenario is that she will score 65 or less, in which case her score will be the mean of the scores she has already achieved.

The best-case scenario is that she will score 100, in which case the 65 will be dropped and her score will be the mean of the other five scores.

 

Example Question #31 : Descriptive Statistics

What is the mean of this data set?

Possible Answers:

Correct answer:

Explanation:

Add the numbers and divide by 6:

Example Question #2037 : Gmat Quantitative Reasoning

If  and , then give the mean of , and .

Possible Answers:

Insufficient information is given to answer this question.

Correct answer:

Explanation:

The mean of , and  is 

 

If you add both sides of each equation:

 

or 

Equivalently,

,

making 290 the mean.

Example Question #14 : Calculating Arithmetic Mean

What is the mean of the following data set in terms of  and ?

Possible Answers:

Correct answer:

Explanation:

Add the expressions and divide by the number of terms, 8.

The sum of the expressions is:

Divide this by 8:

Example Question #15 : Calculating Arithmetic Mean

Julie's grade in a psychology class depends on three tests, each of which are equally weighted; one term paper, which counts half as much as a test; one midterm, which counts for one and one-half as much as a test; and one final, which counts for twice as much as the other tests.

Julie has scored 85%, 84%, and 74% on her three tests, 90% on her term paper, and 72% on her midterm. She is going for an 80% in the course; what is the minimum percent she must score on the final (assuming that 100% is the maximum possible) to achieve this average?

Possible Answers:

She cannot achieve this average this term.

 %

 %

 %

 %

Correct answer:

 %

Explanation:

Let  be her final grade. Julie's final score is calculated as a weighted mean, so we can set up the following inequality:

Simplify and solve for :

Julie must make a minimum of 82% on the final to meet her goal.

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