All GMAT Math Resources
Example Questions
Example Question #5 : Understanding Real Numbers
Today, Becky's age (B) is 3 times Charlie's age. In 3 years, what will Charlie's age be in terms of B?
Today, . In 3 years, .
Example Question #1 : Real Numbers
Given that and , what is the range of possible values for ?
The lowest possible value of is the lowest possible value of divided by the highest possible value of :
The highest possible value of is the highest possible value of divided by the lowest possible value of :
Example Question #4 : Real Numbers
If and are composite integers, which of the following can be prime?
None of these can be prime.
so this is a composite number for all and .
is by definition a composite number.
the product of 2 numbers.
This leaves just . For a number to be prime, it must be odd (except for 2) so we need to have either or be odd (but not both). The first composite odd number is 9. . The smallest composite number is 4. .
is a prime number.
So the answer is
Example Question #2 : Number Theory
If is a real number, which of the following CANNOT be a value for x?
-3
3
122
125
-122
3
The definition of the set of real numbers is the set of all numbers that can fit into a/b where a and b are both integers and b does not equal 0.
So, since we see a fraction here, we know a non-real number occurs if the denominator is 0. Therefore we can find where the denominator is 0 by setting x-3 =0 and solving for x. In this case, x=3 would create a non-real number. Thus our answer is that x CANNOT be 3 for our expression to be a real number.
Example Question #1963 : Problem Solving Questions
Let be the product of integers from 18 to 33, inclusive. If , how many more unique prime factors does have than ?
Greater than
Not enough information given.
This question does not require any calculation. Given that 32 (an even number) is a factor of , then 2 must be a prime factor. If is then multiplied by 2 (to get ) then has no additional unique prime factors (its only additional prime factor, 2, is NOT unique).
Example Question #1 : Understanding Real Numbers
If are both negative, then could NOT be equal to....
is negative and is positive
Therefore, the solution cannot be negative.
Example Question #2 : Real Numbers
If is a real number, which one of these cannot be a value of ?
For the expression to be defined, the denominator needs to be different from 0. Therefore:
So the correct answer is 2.
Example Question #1961 : Problem Solving Questions
If , and , and , what can we say for sure about ?
is positive
is negative
None of the other answers.
None of the other answers.
To show the other answers aren't always true, we need to choose 2 numbers that satisfy the given inequalities but also contradict each answer one-by-one.
Let this choice shows that sometimes , which rules out the answers , is negative, and
Now Let , this will still satisfy the given inequalities, but now . This means that the answer " is positive" isn't always true either.
Example Question #1961 : Problem Solving Questions
Which of the following is equal to the sum of thirty-three one-thousandths and three hundred three ten-thousandths?
Six hundred thirty-three ten-thousandths
Three hundred sixty-six ten-thousandths
Six hundred six ten-thousandths
Three hundred thirty-six ten-thousandths
Six hundred three ten-thousandths
Six hundred thirty-three ten-thousandths
The one-thousandths and ten-thousandths places are the third places and the fourth places, respectively, to the right of the decimal point. Therefore:
Thirty-three one-thousandths =
Three hundred three ten-thousandths =
Add:
The last nonzero digit ends at the ten-thousandths place, so this is , or
six hundred thirty-three ten-thousandths.
Example Question #1962 : Problem Solving Questions
Which of the following is equal to 0.0407?
Four hundred seven ten-thousandths
Four hundred seven one-thousandths
Four hundred seventy ten-thousandths
Four hundred seventy one-thousandths
Forty-seven ten-thousandths
Four hundred seven ten-thousandths
The last nonzero digit is located in the fourth place right of the decimal point - the ten-thousandths place. Put the number, without decimal point or leading zeroes, over 10,000. This number is , or four hundred seven ten-thousandths.