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Relations and Functions — Maths STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 ScienceMathsRelations and Functions1 Mark
MCQ
Set $A$ has three elements and set $B$ has four elements. The number of injections that can be defined from $A$ to $B$ is
  • A
    144
  • B
    12
  • ✓
    24
  • D
    64
✓

Answer

Correct option: C.
24
(c) : Since $3<4$, injective functions from $A$ to $B$ are defined and the total number of such functions is
$
{ }^4 P_3=\frac{4 !}{(4-3) !}=4 \times 3 \times 2 \times 1=24 .
$

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