Question

a boat takes 2hours togo 8km and come back in still water lake with water velocity of 4km per hour.the time taken for going upstreamof 8kmand coning back is what?

Answer 1

From the first condition we can determine the speed of boat....v = 8km / 2hr = 4km/h

...the velocity of water is 0.004km/h

During upstream motion the net velocity would be 4-0.004 = 3.996km/h

So time taken (t) = distance/speed=8 / 3.996 = 2.002hr

During downstream motion net velocity will be 4 + 0.004 = 4.004km/h

=> t = 8 / 4.004 = 1.998hr

one year ago

Disapproved



Time=distance/velocityVbr= 8km/hVrg=4km/hLet t1 and t2 be the time taken by boat to travel in upstream and downstream respectivelyUpstream=8-4=4Downstream=8+4=12T1=8/4=2hrT2=8/12=2/3Total time=2+2/3=2 hr and 40 mins

one year ago

Approved



time = distance/velocity  
when in the direction of current velocity = 8+4= 12 
t1= 8/12 = 2/3 hr 
when against the current velocity 8-4 = 4 
t2= 8/4 = 2 hr. 
total time = 2+ 2/3 = 8/3 hrs. = 2 hrs&40 minutes

5 months ago



Here the speed of water is still. So, they will have equal velocity and equal time taken.

             ☆ Total time = 2 hrs 

                   Time for upstream = 1 hr

                                   downstream = 1 hr 

              ☆ their velocity is 8 kmph each.

So, new downstream velocity will be (8+4) = 12 kmph

       new upstream velocity will be (8-4) = 4 kmph

 

 

              TIME TAKEN = DISTANCE / VELOCITY 

                                                            (distance is 8 km in both cases )

                                      =( 8/12 + 8/4 ) hours 

                                      =( 2/3 + 2 ) hrs 

                                      = 160 mins = 2 hr 40 mins 

Answer 2

time = distance/velocity

when in the direction of current velocity = 8+4= 12

t1= 8/12 = 2/3 hr

when against the current velocity 8-4 = 4

t2= 8/4 = 2 hr.

total time = 2+ 2/3 = 8/3 hrs. = 2 hrs&40 minutes

please mark as brainliest.