Question

Set A has 3 elements and Set B has 4 elements then the number of injective functions that can be defined from Set A to Set B is

(a) 144

(b) 64

(c) 24

(d) 12

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Answer 1

Answer:

To define the injective functions from set A to set B, we can map the first element of set A to any of the 4 elements of set B.

Then the second element can not be mapped to the same element of set A, hence, there are 3 choices in set B for the second element of set A.

Similarly there are 2 choices in set B for the third element of set A.

Hence the total number of injective functions are 4×3×2=24

answer 24

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