$f:\{1,2,3,4,5\}\to \{1,2,3,4\}$ such that $f\left(i\right)=$ even if ‘i’ is even and $f\left(i\right)\le f\left(j\right),fori<j$, than the number of functions are.

$f\left(i\right)=$  even; if I is even and  $f\left(i\right)\le f\left(j\right).i<j$

  
  Element 1 can be mapping to 1 or 2                               1 can be mapping to 1 or 2
  Element 3 can be mapping only 2                                   3 can be mapping 1 or 2 or 3
  Element 5 can be mapping to 2 or 3 or 4                       5 can be mapping to 4

R.N.W=2.1.3=6 ways                                            R.N.W= 2.3.1=6

       1 can be mapping to 1 or 2 or 3 or4
       3 can be mapping  only 4
       5 can be mapping  only 4
      R.N.W = 4ways
     Total R.N.W=16 ways