Folding a paper will make it thickness become double from it before.
Unfolded paper has 1 thickness
1 times folded paper has 2 thickness
2 times folded paper has 4 thickness
3 times folded paper has 8 thickness
From here it is clear that the pattern is [tex] 2^{n} [/tex]. SInce the paper is 0.1mm, then the function would be:
f(n)= [tex] 2^{n} [/tex] x 0.1mm