Question

ritual can now stream 20 km in 2 hours and up stream 4 km in 2 hours find her speed of rowing in still water and speed of current​

Answer 1

Step-by-step explanation:

Let, speed of Ritu in still water be x km/hr

and speed of current be y km/hr

Then speed downstream =(x+y) km/hr

speed upstream =(x−y) km/hr

we know, Time=SpeedDistance

Then x+y20=2 and x−y4=2

⇒x+y=10 ...(1)

&   x−y=2 ...(2)

adding both we get, 2x=12⇒x=6

Thus using (1) y=10−6=4

Hence the speed of Ritu in still water is 6 km/hr and the speed of the current is 4 km/hr.

Answer 2

Answer:

Let Ritu’s speed of rowing in still water and the speed of the stream be x km/h and y km/h respectively.

Ritu’s speed of rowing;

Upstream = ( x - y ) km/h

Downstream = ( x + y ) km/h

According to question,

Ritu can row downstream 20 km in 2 hours,

2( x + y) = 20 [Since, Distance = Speed × Time]

x + y = 10 ....(1)

Ritu can row upstream 4 km in 2 hours,

2( x - y) = 4

x - y = 2 ....(2)

Adding equation (1) and (2), we obtain

x + y + x - y = 10 + 2

2x = 12

x = 6

Putting x = 6 in equation (1), we obtain

6 + y = 10

y = 4

Hence, Ritu’s speed of rowing in still water is 6 km/h and the speed of the stream is 4 km/h.