Question

David is visiting his aunt for the Thanksgiving weekend. He drove 60% of the trip at 40 mph and the rest at ‘x’ mph. The average speed for the entire trip is 50 mph. What is x? A. 60 mph B. 70 mph C. 75 mph D. 80 mph E. 90 mph F. 100 mph

Answer 1

The answer is D.80 mph !!!

Answer 2

D. 80 mph

Explanation:

d- distance

• d/50= 0.6d/40+0.4d/x
• 1/50= 0.3/20+0.4/x
• 0.4/x= 0.02- 0.015
• x= 0.4/0.005
• x= 80 mph