During a trip on an expressway, Ron drove a total of x miles. His average speed on a certain 5-mile section of the expressway was 30 miles per hour, and his average speed for the remainder of the trip was 60 miles per hour. His travel time for the x-mile trip was what percent greater than it would have been if he had traveled at a constant rate of 60 miles per hour for the entire trip?  Choose the most appropriate option.
A) 8.5% B) 50% C) x/12% D) 60/x% E) 500/x%
so Ron drove (x-5) miles at 60mph and 5 miles at 30mph:   (x-5)/60 + (10/60) = (X+5)/60 - current time to drive the whole distance   if the entire trip @60mph than time = x/60   so to get percent [(X+5)/60 ]/[x/60] x100   =(x+5)/x *100   =100+500/x   so increase of 500/x%[/u]=500/x%
<result>E</result>
During a trip on an expressway, Ron drove a total of x miles. His average speed on a certain 5-mile section of the expressway was 30 miles per hour, and his average speed for the remainder of the trip was 60 miles per hour. His travel time for the x-mile trip was what percent greater than it would have been if he had traveled at a constant rate of 60 miles per hour for the entire trip?