Answer: 41.86 miles/hour
Step-by-step explanation:
Use Distance = Speed*Time to find the two missing values with the data that is provided for those two cases [in brackets].
MPH MILES HOURS
50 20 [0.4]
[40] 70 1.75
Totals 90 miles 2.15 hours
Average = 90 miles/2.15 hours
41.86 mph