All GMAT Math Resources
Example Questions
Example Question #53 : Understanding The Properties Of Integers
is a positive integer divisible by 17.
Which of the following numbers cannot be divisible by 17?
Assume each number is positive.
If is divisible by , then for some integer , . In each of the expressions, simplify, replace for , then divide by to determine whether the quotient is an integer:
Simplifying the expression:
Replacing with :
Divide this by 17, and the result is
, an integer.
Simplifying the expression:
Replacing with :
Divide this by 17, and the result is
, an integer.
Simplifying the expression:
Replacing with :
Divide this by 17, and the result is
, an integer.
Simplifying the expression:
Replacing with :
Divide this by 17, and the result is
, an integer.
Simplifying the expression:
Replacing with :
Divide this by 17, and the result is
, not an integer.
is the correct choice.
Example Question #51 : Properties Of Integers
The floor function of any number is written and is the greatest integer which is less than or equal to . Find the value of .
The greatest integer that is less than or equal to is .
The greatest integer that is less than or equal to is .
The greatest integer that is less than or equal to is . is not correct as it is greater than.
Note that for positive decimal numbers, the floor function is the integer part of the number while for negative decimal numbers it is the integer part minus .
Example Question #51 : Understanding The Properties Of Integers
What is the greatest common factor of and , where is a postive integer?
Firstly, we should start by noticing that and are co-prime, which means that they only share 1 as a common factor. It is due to the fact that they are consecutive integers. Also we should notice that will never include since it is the product from all integers from 1 to , therefore, is not a factor of
Example Question #221 : Arithmetic
What is the greatest common factor of and ?
To find the greatest common factor of two numbers, we must first write their respective prime factorization, in other words, we must write these numbers as a product of prime numbers. This can be done by firstly dividing a given number by 2, then 3, and all the way up to higher prime numbers.
and
Then we simply have to multiply all the common factors, with their lowest power:
The common factors here are only 5's, and the lowest power of 5 in both numbers is . Therefore, the greatest common factor is .
Example Question #57 : Understanding The Properties Of Integers
What is the greatest common factor of and ?
We start by writing the prime factorization of these two numbers: and
Note that to find the prime factorization there is not much to do other than just starting with the smallest prime numbers and the GMAT requires to know the prime numbers under 100.
The common factors are only 2's, and we apply to this common factor of the lowest power, which is 1. Therefore, the final answer is .
Example Question #58 : Understanding The Properties Of Integers
What is the greatest common factor of and ?
We start by writing the prime factorization of these two numbers:
and .
By taking the common factors and raising them to the lowest power, we get or , which is the final answer.
Example Question #221 : Arithmetic
What is the least common multiple of and ?
For the least common multiple, we also need to write out the prime factorization of these numbers, as follows:
and .
Then, we multiply all the factors raised to their highest powers.
Here we have: , which is equal to .
Example Question #222 : Arithmetic
What is the least common multiple of and ?
We begin by writing the prime factorization of 78 and 36.
and .
The rule to find the least common multiple is to multiply all factors raised to their highest power.
Here we have: or .
Example Question #222 : Arithmetic
What is the least common multiple of and ?
Let's start by writing the prime factorization of these two numbers:
and .
Then we just have to multiply each factor raised to its highet power for common factors, as follows:
or .
Example Question #1773 : Problem Solving Questions
You know that and that the greatest common divisor of and is . What is the least common multiple of and ?
For any positive integer and , being their least common multiple and being their greatest common factor, then .
Therefore,
or .