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# Formulate the following problems as a pair of equations, and hence find their solutions: (i) Ritu can row downstream 20 km in 2 hours, and upstream 4 km in 2 hours. Find her speed of rowing in still water and the speed of the current. Q.2(1)

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How i go through with this problem i am stuck by solving this question. So please suggest me best way for solving this question Formulate the following problems as a pair of equations, and hence find their solutions: (i) Ritu can row downstream 20 km in 2 hours, and upstream 4 km in 2 hours. Find her speed of rowing in still water and the speed of the current.

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1. Let us consider,

Speed of Ritu in still water = x km/hr

Speed of Stream = y km/hr

Now, speed of Ritu during,

Downstream = x + y km/h

Upstream = x â€“ y km/h

As per the question given,

2(x+y) = 20

Or x + y = 10â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦.(1)

And, 2(x-y) = 4

Or x â€“ y = 2â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦(2)

Adding both the eq.1 and 2, we get,

2x = 12

x = 6

Putting the value of x in eq.1, we get,

y = 4

Therefore,

Speed of Ritu rowing in still water = 6 km/hr

Speed of Stream = 4 km/hr

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