SOLUTION: A certain large city has a circular road around the city and a road directly through downtowm. The speed limit on the cicrular road is 65 mph and the speed limit through downtown i

Algebra ->  Circles -> SOLUTION: A certain large city has a circular road around the city and a road directly through downtowm. The speed limit on the cicrular road is 65 mph and the speed limit through downtown i      Log On


   

Question 276256: A certain large city has a circular road around the city and a road directly through downtowm. The speed limit on the cicrular road is 65 mph and the speed limit through downtown is 35 mph. If the road through downtown is 20 miles long, how long, to the nearest minute, will it take to travel each route?
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


The circumference of the circle is



But you only have to travel half of the circumference to get past the city, so the distance traveled on the circular road would be:



Since distance equals rate times time, , time can be determined by dividing distance by rate:

Hence, the time, in hours, to go around the city is:



Since there are 60 minutes in one hour, the time in minutes to go around the city is:



The path straight through the city is 20 miles and the time, in hours, to travel 20 miles at 35 mph is:



And then in minutes:



You get to do your own arithmetic. Use 3.14 for -- that is plenty close enough. Don't forget to round to the nearest minute.

John