Question

What is the multiplicative inverse of \(\frac{15}{135}\)?

(a) \(\frac{15}{135}\)

(b) \(\frac{-15}{135}\)

(c) 1

(d) 9

This question was posed to me in an interview.

The origin of the question is Properties of Rational Numbers topic in section Rational Numbers of Mathematics – Class 8

Answer 1

Right answer is (d) 9

Best explanation: \(\frac{15}{135}\) * x = 1

Therefore \(\frac{1}{9}\) * x = 1

Therefore x = 9

Multiplicative inverse of a particular number, is the number which gives 1 on multiplication with the number. There is one and only one multiplicative inverse for all numbers.