(1) Sufficient. With the distance known, we could plug it into the rate formula and
computer Bill's rate.
(2) Sufficient. If he covered the same distance at 30 mph as he did at 60 mph, he
must have been travelling at 30 mph for twice as long as he was at 60 mph. Given
that he travelled for 3 hours, he travelled at 30 mph for 2 hours and 60 mph for 1
hour. That comes to 120 miles total distance, and again we solve for the rate.
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