A and B are two sets such that n(A)=4and n(B)=5.If number of possible mappings defined from set A to B is 'x' and out of these 'y' mappings are one-one , then x+y will be=?

1 Answer
F. Javier B.
Apr 27, 2018

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Explanation:

The number of aplications (mappings) between two sets with cardinals n and m respectively is #m^n#

In our case, the number of mappings is #5^4=625=x#

The number of inyective mappings (one to one) is #V_m^n=m(m-1)(m-2)...(m-n+1)# In our case #V_5^4=5·4·3·2=120=y#

#x+y=625+120=745#

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