Functions Ques 4

  1. Let $E=\{1,2,3,4\}$ and $F=\{1,2\}$. Then, the number of onto functions from $E$ to $F$ is

(2001, 1M)

(a) $14$

(b) $16$

(c) $12$

(d) $8$

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Answer:

Correct Answer: 4.(a)

Solution: (a) The number of onto functions from

$E=\{1,2,3,4\}$ to $F=\{1,2\}$

$=$ Total number of functions which map $E$ to $F$ - Number of functions for which map $f(x)=1$ and

$f(x)=2$ for all $x \in E=2^4-2=14$



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