Which number produces a rational number when multiplied by 1 over 5

The answer is - 2/3

Step-by-step explanation:

A rational number is any number that can be expressed as the quotient or fraction p/q of two integers, a numerator p and a non-zero denominator q.

Remember few things,

a rational number times a rational number=rational number

an irrational number times a rational number=irrational number

The number which produces a rational number when multiplied by 1/5 is - 2/3 ... It is not an irrational number but a fraction ...