Each week Manhattan GMAT posts a 700 level GMAT question on our blog and follows up with the answer the next day. Are you up for the challenge?
A survey was sent to 80 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?
(A) 2%
(B) 5%
(C) 14%
(D) 28%
(E) 63%