Danny drove his old car 100 kilometers, from his home to a friend. To prevent the engine from overheating, he stopped his car for 9 minutes every time he completed 40 kilometers of continuous driving. When the car was moving, Danny drove it at an average speed of 60 kilometers per hour. What was Danny's average speed on that trip?	Choose the most appropriate option
A) 37.5 kilometers per hour B) 48 kilometers per hour C) 50.8 kilometers per hour D) 75 kilometers per hour E) 100 kilometers per hour
Time taken to reach first 40 km is 40/60 = 2/3 hr   Time taken to reach next 40 km is 40/60 = 2/3 hr   Time taken to reach next 20 km is 20/60 = 1/3 hr   Danny stopped twice on his way at 40 km from starting point and at 80km from the starting point...   Each stop was of 9 min , so two 9 min break = 2*3/20 =&gt; 3/10 hr   Total time taken to reach 100 km is (2/3 + 2/3 + 1/3+3/10 ) = 59/30 hrs   So, Average speed is 100/(59/30) = 50.8km/hour   Answer will be (50.8 kilometers per hour)
<result>C</result>
Danny drove his old car 100 kilometers, from his home to a friend. To prevent the engine from overheating, he stopped his car for 9 minutes every time he completed 40 kilometers of continuous driving. When the car was moving, Danny drove it at an average speed of 60 kilometers per hour. What was Danny's average speed on that trip?