Question

Let a={1,2,3,4,5} number of functions f from A to A such that f(m) +f(n)=7 whenever m+n = 7

Answer 1

Correct option is A)

A={1,2,3,4,5,6}

f:A→A

∴ Number of onto function=n!

=6!

=6×5×4×3×2×1

∴ Number of onto function=720

Explanation: