Question

Which of the following is not a proposition?
A. 3 is prime.
B. \[\sqrt{2}\] is irrational.
C. Mathematics is interesting.
D. 5 is an even integer.

Answer 1

Hint: To solve this type of problem first we should know the definition of proposition and then the basic definitions of prime numbers, irrational numbers, and integers because these are mentioned in the question.

Complete step-by-step answer:
Definition: A proposition is a declaration that can be either true or false, but not both.
Now we will go through all the options,
Option A: 3 is a prime
From the basics we know that 3 is a prime number.
2, 3, 5, 9, 11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 is a prime number is true.
Option B: \[\sqrt{2}\] is irrational.
By the definition of irrational numbers the given number cannot be written as simple fraction.
\[\sqrt{2}\] is irrational is true.
Option C: Mathematics is interesting.
We cannot say this is either true or false because Mathematics can be interesting for someone, it may not be for someone.
Option D: 5 is an even integer.
We know that 5 is an integer but it is not an even number.
So option D is false.
From above we can conclude that the answer is option C.

Note: This is a direct problem which can be solved by knowing the definition of Proposition. We have to be cautious that the given statement can be either true or false but not both. Take care while checking the statements.