The mathematical expression only seems to complicate things and requires quite a few steps. Thinking about the problem logically, on the other hand, can allow you to deal with (1) in a matter of seconds.
If Dale triples his average speed, then he spends 1/3 less time on the trip. Because he spends 2 hours completing the trip at triple the speed, the original trip would have taken him 6 hours. SUFFICIENT
For (2) we are only given the distance between two cities, A and B. Nowhere is there any rate, so we cannot answer the question. INSUFFICIENT
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