Which One of the Following is an Irrational Number (A) √4 (B) 3√8 (C) √100 (D)-√0.64

Answer: The correct answer for this question has to be option (B) 3√8

Irrational numbers are non-terminating and non-repeating numbers, as we know.

Thus, we can check each of the given options.

√4 = 2, is a rational number

3√8 = 3. 2√2 = 6√2, is an irrational number

√100 = 10, is a rational number

-√0.64 = -0.8 is a rational number

Therefore, option (B) i.e., 3√8 is the correct answer.