A car drives 60 miles on local roads at 20 mph, and 120 miles on the highway at 60 mph, what is the average speed of the entire trip?	Pick one:
A) 36 mph  B) 40 mph  C) 44 mph  D) 52 mph  E) 58 mph
So The Answer is Plainly A....   we have a general relation for speed , time and distance : v (velocity) * t ( time)= d (distance)   for first part we have d=60 miles , and v= 20 mph so we can obtain time : 20*t = 60 Or t= 60/20= 
<gadget id="calculator">60/20</gadget>
<output>3</output>
3 hours the needed time to cover 60 miles   in the same way we should divide 120 to 60 to find the needed time to cover 120 miles ,so t= 2 hours   so the total time for covering total distance would be  3+2= 
<gadget id="calculator"> 3+2</gadget>
<output>5</output>
5 hours and total distance is   60+120= 
<gadget id="calculator">  60+120</gadget>
<output>180</output>
180 miles   Final stage : average speed is total distance divide to total time : 180/5= 
<gadget id="calculator">180/5</gadget>
<output>36</output>
36 miles per hour....
<result>A</result>
A car drives 60 miles on local roads at 20 mph, and 120 miles on the highway at 60 mph, what is the average speed of the entire trip?