Events & Promotions
|
|
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Nov 2211:00 AM IST
-01:00 PM IST
Do RC/MSR passages scare you? e-GMAT is conducting a masterclass to help you learn – Learn effective reading strategies Tackle difficult RC & MSR with confidence Excel in timed test environment- Nov 23
11:00 AM IST
-01:00 PM IST
Attend this free GMAT Algebra Webinar and learn how to master the most challenging Inequalities and Absolute Value problems with ease. 
Nov 2510:00 AM EST
-11:00 AM EST
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors.
10 Apr 2013, 08:10
Kudos
Bookmarks
1. What is the product of three consecutive integers?
(1) At least one of the integers is positive
(2) The sum of the integers is less than 6
2. If x and y are both positive integers and x>y, what the remainder when x is divided by y?
(1) y is a two-digit prime number
(2) x=qy+9, for some positive integer q
3. The length of the median BD in triangle ABC is 12 centimeters, what is the length of side AC?
(1) ABC is an isosceles triangle
(2) AC^2 = AB^2 + BC^2
4. Machine A and B working together at their constant rates can complete a certain task in 6 days. In how many days, working alone, can machine A complete the task?
(1) The average (arithmetic mean) of the respective times A and B would each take to complete the task working alone is 12.5 days.
(2) It would take machine A 5 more days to complete the task alone than it would take machine B to complete the task.
5. Is the standard deviation of list \(A=\{ 3-2x, \ 3-x, \ 3, \ 3+x, \ 3+2x\}\) greater than the standard deviation of list \(B=\{ 3-2x, \ 3-x, \ 3, \ 3+x, \ 3+2x, \ y \}\)?
(1) The standard deviation of list A is positive.
(2) \(y=3\).
6. The ratio of the number of employees of three companies X, Y, and Z is 3:4:8, respectively. Is the average age of all employees in these companies less than 40 years?
(1) The total age of all the employees in these companies is 600 years.
(2) The average age of employees in X, Y, and Z, is 40, 20, and 50 years, respectively.
7. Was the average (arithmetic mean) temperature in degrees Celsius in city A in March less than the average (arithmetic mean) temperature in degrees Celsius in city B in March?
(1) The median temperature in degrees Celsius in City A in March was lower than the median temperature in degrees Celsius in city B.
(2) The ratio of the average temperatures in degrees Celsius in City A and City B in March was 3 to 4, respectively.
8. All marbles in a jar containing 10 marbles are either red or blue. If two marbles are drawn from the jar, at random and without replacement, is the probability that both marbles are red greater than \(\frac{3}{5}\)?
(1) The probability that both marbles selected will be blue is less than \(\frac{1}{10}\).
(2) At least 60% of the marbles in the jar are red.
9. If x is an integer, is x^2>2x?
(1) x is a prime number.
(2) x^2 is a multiple of 9.
10. What is the value of the media of set A?
(1) No number in set A is less than the average (arithmetic mean) of set A.
(2) The average (arithmetic mean) of set A is equal to the range of set A.
The solutions can be found below on this page.
(1) At least one of the integers is positive
(2) The sum of the integers is less than 6
2. If x and y are both positive integers and x>y, what the remainder when x is divided by y?
(1) y is a two-digit prime number
(2) x=qy+9, for some positive integer q
3. The length of the median BD in triangle ABC is 12 centimeters, what is the length of side AC?
(1) ABC is an isosceles triangle
(2) AC^2 = AB^2 + BC^2
4. Machine A and B working together at their constant rates can complete a certain task in 6 days. In how many days, working alone, can machine A complete the task?
(1) The average (arithmetic mean) of the respective times A and B would each take to complete the task working alone is 12.5 days.
(2) It would take machine A 5 more days to complete the task alone than it would take machine B to complete the task.
5. Is the standard deviation of list \(A=\{ 3-2x, \ 3-x, \ 3, \ 3+x, \ 3+2x\}\) greater than the standard deviation of list \(B=\{ 3-2x, \ 3-x, \ 3, \ 3+x, \ 3+2x, \ y \}\)?
(1) The standard deviation of list A is positive.
(2) \(y=3\).
6. The ratio of the number of employees of three companies X, Y, and Z is 3:4:8, respectively. Is the average age of all employees in these companies less than 40 years?
(1) The total age of all the employees in these companies is 600 years.
(2) The average age of employees in X, Y, and Z, is 40, 20, and 50 years, respectively.
7. Was the average (arithmetic mean) temperature in degrees Celsius in city A in March less than the average (arithmetic mean) temperature in degrees Celsius in city B in March?
(1) The median temperature in degrees Celsius in City A in March was lower than the median temperature in degrees Celsius in city B.
(2) The ratio of the average temperatures in degrees Celsius in City A and City B in March was 3 to 4, respectively.
8. All marbles in a jar containing 10 marbles are either red or blue. If two marbles are drawn from the jar, at random and without replacement, is the probability that both marbles are red greater than \(\frac{3}{5}\)?
(1) The probability that both marbles selected will be blue is less than \(\frac{1}{10}\).
(2) At least 60% of the marbles in the jar are red.
9. If x is an integer, is x^2>2x?
(1) x is a prime number.
(2) x^2 is a multiple of 9.
10. What is the value of the media of set A?
(1) No number in set A is less than the average (arithmetic mean) of set A.
(2) The average (arithmetic mean) of set A is equal to the range of set A.
The solutions can be found below on this page.
Experience GMAT Club Test Questions
Yes, you've landed on a GMAT Club Tests question
Craving more? Unlock our full suite of GMAT Club Tests here
Want to experience more? Get a taste of our tests with our free trial today
Rise to the challenge with GMAT Club Tests. Happy practicing!
14 Apr 2013, 09:02
Kudos
Bookmarks
5. Is the standard deviation of list \(A=\{ 3-2x, \ 3-x, \ 3, \ 3+x, \ 3+2x\}\) greater than the standard deviation of list \(B=\{ 3-2x, \ 3-x, \ 3, \ 3+x, \ 3+2x, \ y \}\)?
First, note that the mean of list A is \(\frac{(3-2x) +(3-x)+3+(3+x)+(3+2x)}{5}=3\). Additionally, it's important to note that list B is simply list A with the addition of the element \(y\).
(1) The standard deviation of list A is positive.
We know that the standard deviation of any list is greater than or equal to zero. The standard deviation of a list is zero only when the list consists of identical elements. So, this statement implies that list A does NOT consist of identical elements or that \(x\) does not equal zero. However, this statement is not sufficient to answer the question.
(2) \(y=3\).
We know that the mean of list A is 3. If \(x \neq 0\) (e.g., if \(x=1\)), then \(A=\{1, \ 2, \ 3, \ 4, \ 5\}\) and \(B = \{1, \ 2, \ 3, \ 3, \ 4, \ 5\}\). The standard deviation of B would be smaller than the standard deviation of A, since the elements of B are less widespread than the elements of list A. However, if \(x=0\), then \(A=\{3, \ 3, \ 3, \ 3, \ 3\}\) and \(B=\{3, \ 3, \ 3, \ 3, \ 3, \ 3\}\), so both will have a standard deviation of zero. This statement alone is not sufficient.
(1)+(2) We know that the mean of list A is 3 and it does not consist of identical elements. Since \(y=3\), then list B is list A with the addition of the element 3. The addition of a new element equal to the mean in list B makes list B less widespread than list A, resulting in a decrease in the standard deviation. Consequently, \(SD(A) \gt SD(B)\). Combining both statements provides sufficient information to answer the question.
Answer: C
First, note that the mean of list A is \(\frac{(3-2x) +(3-x)+3+(3+x)+(3+2x)}{5}=3\). Additionally, it's important to note that list B is simply list A with the addition of the element \(y\).
(1) The standard deviation of list A is positive.
We know that the standard deviation of any list is greater than or equal to zero. The standard deviation of a list is zero only when the list consists of identical elements. So, this statement implies that list A does NOT consist of identical elements or that \(x\) does not equal zero. However, this statement is not sufficient to answer the question.
(2) \(y=3\).
We know that the mean of list A is 3. If \(x \neq 0\) (e.g., if \(x=1\)), then \(A=\{1, \ 2, \ 3, \ 4, \ 5\}\) and \(B = \{1, \ 2, \ 3, \ 3, \ 4, \ 5\}\). The standard deviation of B would be smaller than the standard deviation of A, since the elements of B are less widespread than the elements of list A. However, if \(x=0\), then \(A=\{3, \ 3, \ 3, \ 3, \ 3\}\) and \(B=\{3, \ 3, \ 3, \ 3, \ 3, \ 3\}\), so both will have a standard deviation of zero. This statement alone is not sufficient.
(1)+(2) We know that the mean of list A is 3 and it does not consist of identical elements. Since \(y=3\), then list B is list A with the addition of the element 3. The addition of a new element equal to the mean in list B makes list B less widespread than list A, resulting in a decrease in the standard deviation. Consequently, \(SD(A) \gt SD(B)\). Combining both statements provides sufficient information to answer the question.
Answer: C
14 Apr 2013, 09:00
Kudos
Bookmarks
2. If \(x\) and \(y\) are both positive integers and \(x \gt y\), what the remainder when \(x\) is divided by \(y\)?
Given that \(x\) and \(y\) are positive integers, there exist unique integers \(q\) and \(r\), called the quotient and remainder, respectively, such that \(x = yq + r\) and \(0 \leq r < y\).
(1) \(y\) is a two-digit prime number.
This statement is clearly insufficient, as we have no information about \(x\).
(2) \(x=qy+9\), for some positive integer \(q\).
It might be tempting to consider this statement sufficient and conclude that \(r = 9\), given that the equation resembles \(x = yq + r\). However, we don't know whether \(y > 9\): the remainder must be less than the divisor.
For example:
If \(x = 10\) and \(y = 1\), then \(10 = 1*1 + 9\), but the remainder upon dividing 10 by 1 is zero.
If \(x = 11\) and \(y = 2\), then \(11 = 1*2 + 9\), but the remainder upon dividing 11 by 2 is one.
Not sufficient.
(1)+(2) From (2), we know that \(x = qy + 9\), and from (1), we know that \(y\) is greater than 9 (since it's a two-digit number). Thus, we have a direct formula for the remainder, as given above. Sufficient.
Answer: C
Given that \(x\) and \(y\) are positive integers, there exist unique integers \(q\) and \(r\), called the quotient and remainder, respectively, such that \(x = yq + r\) and \(0 \leq r < y\).
(1) \(y\) is a two-digit prime number.
This statement is clearly insufficient, as we have no information about \(x\).
(2) \(x=qy+9\), for some positive integer \(q\).
It might be tempting to consider this statement sufficient and conclude that \(r = 9\), given that the equation resembles \(x = yq + r\). However, we don't know whether \(y > 9\): the remainder must be less than the divisor.
For example:
If \(x = 10\) and \(y = 1\), then \(10 = 1*1 + 9\), but the remainder upon dividing 10 by 1 is zero.
If \(x = 11\) and \(y = 2\), then \(11 = 1*2 + 9\), but the remainder upon dividing 11 by 2 is one.
Not sufficient.
(1)+(2) From (2), we know that \(x = qy + 9\), and from (1), we know that \(y\) is greater than 9 (since it's a two-digit number). Thus, we have a direct formula for the remainder, as given above. Sufficient.
Answer: C
