Let E = {1, 2, 3, 4} And F = {a, b}. Then The Number Of Onto Functions From E To F Is

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Question

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

Solution

Correct option is

14

We first find the number of functions from E to F.  

We can assign 1 to one of the two values a or b. Similarly, we can assign 2, 3 and 4 to one of the two values a or b. Thus, there are 2 × 2 × 2 × 2 = 16 functions from E to F. out of these functions the two constant functions.  

              

          

are not onto functions.  

∴ there are 16 – 2 = 14 onto functions from E to F.

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