Which number produces a rational number when multiplied by 0.4

A.

B.

D.

Step-by-step explanation:

A rational number is a real number that can be expressed as

Where, p and q are any integers,

Such that q ≠ 0,

If a real number is not rational then it is irrational.

Also, the product of two rational number is always a rational number while the product of a rational number and an irrational number is always an irrational number,

And, a non terminating recurring decimal and square root of a perfect square number are always a rational number,

Here, , 0.444....., √9 and 0.4 are rational number,

⇒ 0.4 × 2/7, 0.4 × 0.4444...  and  0.4 × √9 are rational number.

Therefore, option A, B and D are correct.