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Choose the correct option.
If set A contains four elements and set B contains five elements, then the number of one-one and…
If set $A$ contains four elements and set $B$ contains five elements, then the number of one-one and onto mapping from $A \to B$ is:
- a120
- b0
- c720
- d20
Answer
Answer
Correct option: b
Answer: (b) 0
A function from set $A$ to set $B$ can be both one-one and onto (bijective) only if the two sets have the same number of elements. Since $n(A) = 4$ and $n(B) = 5$, no mapping can be onto, so the number of one-one and onto mappings is 0.