Question 304384
Andy's average driving speed for a 4 hour trip was 45 miles per hour. During the first 3 hours he drove 40 miles per hour. What was his average speed for the last hour on his trip.

average for total trip = 45 mph
trip was for 4 hours 

distance traveled = 45*4= 180 miles

3 hours he drove a 40 mph= 120 miles

Balance 180-120 = 60 miles he drove in 1 hour

average speed for last hour = 60 mph

Ananth