A Truck drives 80 miles on local roads at 30 mph, and 50 miles on the highway at 60 mph, the truck also take a hour lunch break. what is the average speed of the entire trip?	Choose the correct choice.
A) 30 mph  B) 29 mph  C) 28 mph  D) 31 mph  E) 23 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=80 miles , and v= 30 mph so we can obtain time : 30*t = 80 Or t= 80/30 = 2.6 hours the needed time to cover 80 miles   in the same way we should divide 50 to 60 to find the needed time to cover 50 miles ,so t= 0.8 hours   so the total time for covering total distance would be 2.6+0.8+1 (lunch time) = 4.4 hours and total distance is   80+50= 
<gadget id="calculator">  80+50</gadget>
<output>130</output>
130 miles   Final stage : average speed is total distance divide to total time : 130/4.4= 29.5 miles per hour rounding up to 30....
<result>A</result>
A Truck drives 80 miles on local roads at 30 mph, and 50 miles on the highway at 60 mph, the truck also take a hour lunch break. what is the average speed of the entire trip?