The number of possible surjection from A={1,2,3,...n} to B={1,2} (where n≥2) is 62, then n=
A
5
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B
6
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C
7
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D
8
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Solution
The correct option is A6 Each element in A can be mapped onto any of two elements of B ∴ Total possible functions are 2n For the fn′s to be surjections , they shouldn't be mapped alone to any of the two elements. ∴ Total no of surjections =2n−2 2n−2=62 ⇒n=6