If n(A)= 3 , n(B)= 5 Find the number  of onto function from A to B

  • Option 1)

    150

  • Option 2)

    120

  • Option 3)

    200

  • Option 4)

    none of these

 

Answers (1)
H Himanshu

As we have learned

Number of Onto function -

f:A\rightarrow B

Such\: that\: n\left ( A \right )= m

&                    n\left ( B\right )=n

m\geqslant n

Number of onto functions = \sum_{r=1}^{n}\left ( -1 \right )^{n-r}n_{C_{r}}r^{m}

-

 

 For onto function n(A)> n(B) otherwise ; it will always be an inoto function 

there are zero onto function   

 


Option 1)

150

Option 2)

120

Option 3)

200

Option 4)

none of these

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