Lauren drove the 75 miles to the coast at 75mph, but got stuck in traffic and averaged 25mph on the way back. -How many total miles did Lauren drive in this round-trip?
-How many total hours did Lauren drive in this round-trip?
-What was the average speed Lauren was driving during this round-trip?

Step-by-step explanation:

1) The distance that Lauren drove to the coast is the same as the distance he drove back from the coast. It means that the total miles that Lauren drove in this round-trip is

75 + 75 = 150 miles

2) time = distance/speed

Time spent in driving to the coast is

75/75 = 1 hour

His return speed is 25 mph

Time spent in driving back from the coast is

75/25 = 3 hours

3) Average speed = total distance/total time

Total distance = 75 + 75 = 150 miles

Total time = 1 + 3 = 4 hours

Average speed = 150/4 = 37.5 mph

a is the correct