Question

A number which is a factor of every number is
$
  {\text{A}}{\text{. 0}} \\
  {\text{B}}{\text{. 1}} \\
  {\text{C}}{\text{. 2}} \\
  {\text{D}}{\text{. None}} \\
$

Answer 1

Hint – To find the answer, we verify if each of the option is a factor of prime numbers and composite numbers individually. If yes, the number is a factor of every number.
Complete step-by-step answer::
Given data,
A number which is a factor of every number.
Let us consider 0,
0 is only a factor of itself. It is not a factor of any other number.
Let us consider 1,
Let us consider prime and composite numbers separately and see if 1 is a factor in each case:
Prime Numbers,
Example: 7
The factors of 7 are 7 and 1.
Composite Numbers,
Example: 10
The factors of 10 are 10, 5, 2 and 1.
Hence 1 is a factor of both prime and composite numbers, i.e. all numbers.
Let us consider 2,
2 is a factor to only composite numbers, such as 4, 10, 86, 44. But not any prime numbers.
Hence Option B is the correct answer.
Note – In order to solve questions of this type the key is to check if the given number is a factor of prime and composite numbers separately. We should also know the definition of prime and composite numbers.
Prime numbers are those which have only two factors, 1 and itself.
Composite number is a positive number that can be formed by multiplying two smaller numbers.