we will consider 0 as even number

from 1 to 10 there are 4 integers that contain no odd digits

from 10 to 19 all the numbers contain the odd digit 1

from 20 to 29 there are 5 integers that contain no odd digits

from 30 to 39 all the numbers contain the odd digit 3

from 40 to 50 there are 5 integers that contain no odd digits

thus the total number of integers that contain no odd digits is 4 + 5 + 5 = 14

14/50 = 0.28 or 28% of the first 50 positive integers contain no odd digits.