Question

A man can row2/3 rd of a kilo meter down stream in 5 minutes and return to the starting point in another
10 minutes. The speed of the man in still water is_ kmph.
ream, then the speed of the​

Answer 1

Answer:

Let he speed of the man be x km/hr and that of the water current be y km/hr.

While going upstream, the relative speed of the man w.r.t stream is x−y km/hr.

While going downstream, the relative speed of the man w.r.t stream is x+y km/hr.

As per given condition,

x−y

3/4

=11

4

1

min and

x+y

3/4

=7

2

1

min

Dividing the above 2 equations,

x−y

x+y

=

2

3

→2(x+y)=3(x−y)

→5y=x

Putting this value of x in equation 2:

6x/5

3/4

=

120

15

x=5 km/hr

Answer 2

We can write three - quarters of a kilometer as 750 meters and 1114

1114

minutes as 675 seconds

Rateupstream=750675m/sec=109m/secRatedownstream=750450m/sec=53m/sec∴Rateinstillwater=12(109+53)m/sec=2518m/sec=(2518×185)km/hr=5km/hr

Rateupstream=750675m/sec=109m/secRatedownstream=750450m/sec=53m/sec∴Rateinstillwater=12(109+53)m/sec=2518m/sec=(2518×185)km/hr=5km/hr