Math, asked by ROARING, 10 months ago


6. A can row a certain distance down a stream in 6 hrs. and return the same distance in 9 hours. If the stream flows at the rate of 2.25 km per hour,
find how far he can row in an hour in still water.​

Answers

Answered by Ayushbhat
0

Answer:

Letthedistancetravelled=dkm

Giventhatthespeedoftheboatinstillwater=6km/hrand

thespeedofthewatercurrent=2km/hr.

∴Therelativespeeddownstream=(6+2)km/hr=8km/hr.

Sothetimetakendownstream=

relativespeed

distance

=

8

d

hr.

Againtherelativespeedupstream=(6−2)km/hr=4km/hr.

thetimetakenupstream=

relativespeed

distance

=

4

d

hr.

∴Thetotaltimeforgoingdownandcomingup

=(

8

d

+

4

d

)=

8

3d

hr

Alsothetotaldistanceforgoingdownandcomingup=d+d=2d.

∴Averagespeed=

totaltimetaken

totaldistance

=

8

3d

2d

=

3d

2d×8

km/hr=

3

16

km/hr.

Ans−OptionB.

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