All GRE Subject Test: Math Resources
Example Questions
Example Question #1 : Other Topics
Find the mean of the following set of numbers:
The mean can be found in the same way as the average of a group of numbers. To find the average, use the following formula:
So, if our set consists of
We will get our mean via:
So our answer is
Example Question #1 : Other Topics
The mean of four numbers is .
A: The sum of the four numbers.
B:
Can't be determined from the given information.
Quantity A is greater.
Both are equal.
Quantity B is greater.
Both are equal.
To find the sum of the four numbers, just multiply four and the average. By multiplying the average and number of terms, we get the sum of the four numbers regardless of what those values could be.
Since Quantity A matches Quantity B, answer should be both are equal.
Example Question #1 : Probability & Statistics
Mean of is
.
are all positive integers.
is between
and
inclusive.
A: Mean of .
B: Mean of .
Quantity B is greater.
Can't be determined from the information above.
Quantity A is greater.
Both are equal.
Can't be determined from the information above.
Let's look at a case where .
Let's have be
and
be
. The sum of the three numbers have to be
or
.
The average of is
or
. The avergae of
is
or
.
This makes Quantity B bigger, HOWEVER, what if we switched the and
values.
The average of is still
or
. The avergae of
is
or
.
This makes Quantity A bigger. Because we have two different scenarios, this makes the answer can't be determined based on the information above.
Example Question #1 : Other Topics
If and are positive integers from
inclusive, then:
A: The mean of
B: The mean of
Quantity B is greater
Both are equal
Can't be determined from the information above
Quantity A is greater
Can't be determined from the information above
Let's add each expression from each respective quantity
Quantity A:
Quantity B:
Since we will let
and
. The sum of Quantity A is
and the sum of Quantity B is also
. HOWEVER, if
was
, that means the sum mof Quantity B is
. With the same number of terms in both quantities, the larger sum means greater mean. First scenario, we would have same mean but the next scenario we have Quantity B with a greater mean. The answer is can't be determined from the information above.
Example Question #1 : Other Topics
John picks five numbers out of a set of seven and decides to find the average. The set has .
A: John averages the five numbers he picked from the set.
B:
Quantity B is greater
Quantity A is greater
Can't be determined from the information above
Both are equal
Quantity B is greater
To figure out which Quantity is greater, let's find the highest possible mean in Quantity A. We should pick the biggest numbers which are
. The mean is
. This is the highest possible mean and since Quantity B is
this makes Quantity B is greater the correct answer.
Example Question #1 : Statistics
Find the mean.
To find the mean, add the terms up and divide by the number of terms.
Example Question #1 : Other Topics
Find if the mean of
is
.
To find the mean, add the terms up and divide by the number of terms.
Then add the numerator.
Cross-multiply.
Subtract
on both sides.
Example Question #1 : Mean
If average of and
is
and
is
what is the average of
?
If the average of and
is
, then the sum must be
.
If we add the sum of we get
or
.
To find the average of the three terms, we divide and
to get
.
Example Question #1 : Statistics
What is the average of the first ten prime numbers?
The first ten prime numbers are . Prime numbers have two factors:
and the number itself. Then to find mean, we add all the numbers and divide by
.
Example Question #2 : Statistics
If the average of seven consecutive numbers is , what is the value of the second number in the set?
There are two methods.
Method 1:
Since the average of consecutive number is
, we can express this as:
Cross-multiply
Subtract
on both sides then divide both sides by
Since we are looking for the second term, just plug into expression
. That means answer is
or
.
Method 2:
Since the average of consecutive number is
, this means the median is also
. Consecutive means one after another and with each term having the same difference, we know the mean equals the median. Since there are
terms, the median will have
terms left and right of it. Then, the series will go
. The second term is
.
All GRE Subject Test: Math Resources
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