Official Solution: The average speed equals to \(\frac{\text{total distance}}{\text{total time}}\).

Say the distance between the town and the village is \(d\) kilometers, and the speed from the village to town is \(x\) kilometers per hour, then \(\frac{\text{total distance}}{\text{total time}}=\frac{d+d}{\frac{d}{60}+\frac{d}{x}}\). \(d\) can be reduced, and we get \(\text{speed}=\frac{2}{\frac{1}{60}+\frac{1}{x}}\). So, as you can see we only need to find the average speed from the village to town.

(1) In the evening, John drove at a constant speed of 40 kilometers per hour. Sufficient.

(2) John's morning drive lasted 2 hours. We know nothing about his evening drive. Not sufficient.

Answer: A

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