In order to find the solution, you must find a common denominator.
A good common denominator for these 2 fractions is 40 because 5 times 8 is 40 and 8 times 5 is 40.
For 1/5, multiply the 1 by 8 because you multiplied the 5 by 8 and you must do the same thing you did to the denominator to the numerator, so 1 times 8 is 8.
1/5 = 8/40
You do the same thing to 2/8 except multiply by 5.
2 times 5 is 10.
2/8 = 10/40
Now you have the fractions 8/40 and 10/40.
10/40 is greater than 8/40, so 10/40 > 8/40.
10/40 = 2/8
2/8 is greater than 1/5.
Hope this helps. :)