Medium MCQ +4 / -1 PYQ · JEE Mains 2021

Consider function f : A $\to$ B and g : B $\to$ C (A, B, C $\subseteq$ R) such that (gof)$-$1 exists, then :

  1. A f and g both are one-one
  2. B f and g both are onto
  3. C f is one-one and g is onto Correct answer
  4. D f is onto and g is one-one

Solution

$\therefore$ (gof)<sup>$-$1</sup> exist $\Rightarrow$ gof is bijective<br><br>$\Rightarrow$ 'f' must be one-one and 'g' must be ONTO.

About this question

Subject: Mathematics · Chapter: Sets, Relations and Functions · Topic: Sets and Operations

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