A survey was sent to 70 customers, 7 of whom responded. Then the survey was redesigned and sent to another 63 customers, 9 of whom responded. By approximately what percent did the response rate increase from the original survey to the redesigned survey?	Pick one:	A) 2%	B) 6%	C) 4%	D) 28%	E) 63%
case 1: (7/70)=x/100   x=10%   case 2: (9/63)=y/100   y=14%   So percent increase is =(y-x)=(14-10)= 
<gadget id="calculator">(14-10)</gadget>
<output>4</output>
4%   Answer is 4%
<result>C</result>
A survey was sent to 70 customers, 7 of whom responded. Then the survey was redesigned and sent to another 63 customers, 9 of whom responded. By approximately what percent did the response rate increase from the original survey to the redesigned survey?