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Pratap rowed 18 miles down the Delaware River in 2 hrs., but the return trip took 4 1/2 hrs. Find the rate Pratap can row in both stillwater and current.

Math58  Nov 30, 2014

Best Answer 

 #2
avatar+91436 
+8

18/2=9m/hour with the current        P+C=9   (1)

18/4.5=4m/h against the current      P-C=4    (2)

(1)+(2)

2P+C-C=13

2P=13

P=6.5m/h

sub into (1)

6.5+C=9

C=2.5m/h

 

so Pratap can row 6.5m/h and the current is flowing at 2.5m/h

Melody  Nov 30, 2014
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2+0 Answers

 #1
avatar+62 
+5

The part of the question 'stillwater and current' can be interpretted to ways:

1) The current is pushing him in the right direction getting him a time of 2 hours.

 OR

2) The current is pushing against him getting him a time of 4 and a half hours.

I would guess that the question is refering to the view 2. So all you have to do is 18m divided by 2hrs and 18m divided by 4 and a half hrs. Getting 9m/h for still water and 4m/h for fighting against the curent.

NathanDeAlien  Nov 30, 2014
 #2
avatar+91436 
+8
Best Answer

18/2=9m/hour with the current        P+C=9   (1)

18/4.5=4m/h against the current      P-C=4    (2)

(1)+(2)

2P+C-C=13

2P=13

P=6.5m/h

sub into (1)

6.5+C=9

C=2.5m/h

 

so Pratap can row 6.5m/h and the current is flowing at 2.5m/h

Melody  Nov 30, 2014

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