Question 370236
The speed of the boat in still water is 28 mph. the boat traveled 70 miles per hour downstream in the same amount of time that it took to travel 42 miles upstream. What is the rate of current of the river?
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let rate of current be x mph
rate of boat in still water = 28mph
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Upstream rate = 28-x mph
downstream rate = 28+x
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upstream distance = 42 miles
downstream distance = 70 miles
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t= d/r
upstream time = downstream time
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42/(28-x) = 70/x
42x=70(28-x)
42x=1960-70x
42x+70x=1960
112x=1960
/112
x= 1960/112
x= 17.5 mph. the rate of current
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m.ananth@hotmail.ca