What percentage of numbers from 1 to 60 have 1 or 9 in the unit's digit? Options:  A) 12  B) 14.11  C) 18.33  D) 20  E) 21
Clearly, the numbers which have 1 or 9 in the unit's digit, have squares that end in the digit 1. Such numbers from 1 to 60 are 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59   Number of such number =11   ANSWER :18.33
<result>C</result>
What percentage of numbers from 1 to 60 have 1 or 9 in the unit's digit?