The folder will lose 36% in size.
Of its previous size 100%, it will lose 36%
100 - 36 = 64
So after compression the file will be 64% of it's original size.
The new compressed size will be 17.5 * 64%.
We need to convert our percent to a decimal value so we can apply the multiplication.
17.5 * .64 = 11.2 MB