the clarke family went sailing on a lake. Their boat averaged 6 kilometers per hour. The Rourke family took thier outboard runabout for a trip on the lake for the same amount of time. Their family traveled 20 kilometers farther than the Clarke family. How many hours did each family spend on their boat trip?

let the time spent = x hr.

distance covered by clarke = 6x km

so, distance covered by rourke = 6x+20 km

time taken = x hr = (6x+20)/14

=>x = 2.5 hrs.