a survey was sent to 80 customers , 9 of whom responded . then the survey was redesigned and sent to another 63 customers , 12 of whom responded . by approximately what percent did the response rate increase from the original survey to the redesigned survey ?
"rate of first survey = 9 / 80 rate of second survey = 12 / 63 % response rate increase ( 12 / 63 - 9 / 80 ) / ( 9 / 80 ) = 69 % answer is e = 69 %"
floor(multiply(subtract(divide(12, 63), divide(9, 80)), const_100))