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 ?
"case 1 : ( 7 / 80 ) = x / 100 x = 9 % case 2 : ( 9 / 63 ) = y / 100 y = 14 % so percent increase is = ( y - x ) = ( 14 - 9 ) % = 5 % answer is b"
floor(multiply(subtract(divide(9, 63), divide(7, 80)), const_100))