What percentage of numbers from 1 to 70 have 1 or 9 in the unit's digit?
Answers
A) 6 B) 9 C) 24 D) 20 E) 29
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 70 are 1, 9, 11, 19, 21, 29, 31, 39, 41, 49, 51, 59, 61, 69.   Number of such number =14   Required percentage =14	x 100	% = 20%   Answer:24
<result>C</result>
What percentage of numbers from 1 to 70 have 1 or 9 in the unit's digit?