Question 616514
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Hi, 
A man rowed 3 miles upstream in 90 minutes
Let r represent the rowing r
D = rt OR r = D/t
(r-2) = 3/1.5 = 2
  r-2 = 2
  r = 4mi/hr
With the current, will travel 6mi/hr
{{{ 3mi/6(mi/hr) = .5hr}}} or 30min