Yes, this problem is really hard but it is solved.
Let,
No of stickers Mark had = 'a'
" " " Nathan had = 'b'
" " " Owen had = 'c'
Given,
12.5% of Mark's stickers = 25% of Nathan's stickers
---> a = 2 * b
a = 26 ---> b = a/2
No of stickers Owen had = 1/4th of Number of stickers Mark had
C = 1/4 * a
a = 4c --> C = a/4
a) Ratio of all three is
a : b : c
a : a/2 : a/4
1 : 1/2 : 1/4
= 4 : 2 : 1
b) Nathan gave 58 to Mark,
then Owen had 1/5 of Mark's stickers
--> C = 1/5 * (a + 58)
--> 5c = a + 58
we (know) a = 4c
5c = 4c + 58
C = 58
--> a = 4 * 58 = 232
b = a/2 = 232/2 = 116
Total stickers = a + b + c
= 232 + 116 + 58
= 406
Total = 406