Question 1207696
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She travels equal distances at the two speeds of 2mph and 7mph.<br>
Since the ratio of speeds is 2:7 and the distances are the same, the ratio of times spent at the two speeds is 7:2.<br>
We can calculate her average speed as a weighted average -- she spends 7/9 of her time at 2mph and 2/9 of her time at 7mph; her average speed is<br>
(7/9)*2+(2/9)*7 = 14/9+14/9 = 28/9<br>
ANSWER: 28/9 mph, or 3 1/9 mph<br>