If the man drives at a speed of 60 mph for 3 hours, then he traveled a distance of 60 mph x 3 hours = 180 miles.
To achieve an average speed of 70 mph over a total of 5 hours (3 hours + 2 hours), the man needs to travel a total distance of 70 mph x 5 hours = 350 miles.
If he has already traveled 180 miles, then he needs to travel an additional 350 miles - 180 miles = 170 miles in the next 2 hours.
To maintain a speed over 2 hours to cover a distance of 170 miles, the man needs to drive at a speed of 170 miles / 2 hours = 85 mph.
Therefore, the man would need to maintain a speed of 85 mph over the next 2 hours in order to achieve an average speed of 70 mph.
#### 85
The answer is: 85
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
If a man drives at a speed of 60 mph for 3 hours, what speed would he need to maintain over the next 2 hours in order to achieve an average speed of 70 mph?

### Answer:
