All SAT Math Resources
Example Questions
Example Question #61 : Factors / Multiples
If , where are all positive integers, what is ?
4
5
3
7
6
5
We will essentially have to represent 180 as a product of prime factors, because 2, 3, 5, and 7 are all prime numbers. The easiest way to do this will be to find the prime factorization of 180.
180 = 18(10)= (9)(2)(10) = (3)(3)(2)(10)=(3)(3)(2)(2)(5) = . Because 7 is not a factor of 180, we can mutiply the prime factorization of 180 by (which equals 1) in order to get 7 into our prime factorization.
=
In order for to equal , the exponents of each base must match. This means that a = 2, b = 2, c = 1, and d = 0. The sum of a, b, c, and d is 5.
The answer is 5.
Example Question #61 : Factors / Multiples
What is the product of the distinct prime factors of 24?
The prime factorization of 24 is (2)(2)(2)(3). The distinct primes are 2 and 3, the product of which is 6.
Example Question #62 : Factors / Multiples
How many prime factors does have?
Since 7 is prime, its only prime factor is itself.
Example Question #31 : Factors / Multiples
What is the smallest positive multiple of 12?
Multiples of 12 are found by multiplying 12 by a whole number. Some examples include:
Clearly, the smallest positive value obtainable is 12. Do not confuse the term multiple with the term factor!
Example Question #31 : Factors / Multiples
How many prime factors of 210 are greater than 2?
one
three
four
five
two
three
Begin by identifying the prime factors of 210. This can be done easily using a factoring tree (see image).
The prime factors of 210 are 2, 3, 5 and 7. Of these factors, three of them are greater than 2.
Example Question #61 : Factors / Multiples
How many integers between 50 and 100 are divisible by 9?
6
5
7
9
8
6
The smallest multiple of 9 within the given range is .
The largest multiple of 9 within the given range is .
Counting the numbers from 6 to 11, inclusive, yields 6.
Example Question #14 : Other Factors / Multiples
is the set of all positive multiples of , and is the set of all squares of integers. Which of the following numbers belongs to both sets?
is the only choice that is both a multiple of and a perfect square.