You are traveling to Chicago for a job interview. You leave Toledo, Ohio, at 5:45 A.M. and arrive in Elkhart, Indiana, at 8:15 A.M.. The distance from Toledo to Elkhart is 136 miles; the distance from Toledo to Chicago is 244 miles. The speed limit is 65 mph. What is the minimum speed you must maintain in order to arrive in Chicago before 10:30 A.M.

The minimum speed will be calculated as follows:
Time taken from Toledo to Elkhart=(8.15-5.45)=2 1/2 hours
Distance=136 miles
thus the speed between Toledo and Elkhart= 136 miles/2.5=54.4 mph

Distance between Toledo and Chicago is 244 miles
Distance between Elkhart and Chicago=244-136=108 miles
time taken to travel between Elkhart and Chicago assuming that I left Elkhart at exactly 8:15 and reach at 10.30:
=10:30-8:15=2.25 hours
thus the speed will be:
speed=(108)/(2.25)=48 mph
Thus for us to get to Chicago by 10:30 a.m we should drive at 48 mph