desi_chick

hi i don't get the following question, need explanations:

-A car traveled 10 miles at an average speed of 20mph and then traveled to the next 10 miles at an average speed of 40mph. What was the average speed in miles per hour of the car for the 20 miles?

Answer: 80/3

thnxs.

anhtimmy

Trip 1:
-10 miles
-20 mph
-time: .5h

Trip 2:
-10 miles
-40 mph
-time: .25h

total distance/total time
20/.75 -> convert to writable fraction -> 80/3

boonshakalaka?