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📐 Mathematics  ·  Relations and Functions (Class 12)  ·  JEE

If f : A → B and g : B → C are both onto, then g∘f is:

Answer: Onto.

  • A One-one but not necessarily onto
  • B Neither one-one nor onto
  • C Bijective in every case
  • D Onto

Correct answer: D. Onto

Explanation: Each c ∈ C has a preimage b under g, and that b has a preimage a under f, so g(f(a)) = c.

Concept context

Types of relations, equivalence classes, one-one and onto functions, composition, and invertible functions

Read the full Relations and Functions (Class 12) notes →