What percentage of numbers from 1 to 70 have 1 or 9 in the unit's digit?
Choose the correct choice from the following answers:	A) 4%	B) 13%	C) 20%	D) 23%	E) 26%
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 % = (14/70)x100 % =20%   answer :20%
<result>C</result>
What percentage of numbers from 1 to 70 have 1 or 9 in the unit's digit?