# Aptitude - Boats and Streams - Discussion

Discussion Forum : Boats and Streams - General Questions (Q.No. 3)
3.
A boat running upstream takes 8 hours 48 minutes to cover a certain distance, while it takes 4 hours to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively?
2 : 1
3 : 2
8 : 3
Cannot be determined
None of these
Explanation:

Let the man's rate upstream be x kmph and that downstream be y kmph.

Then, distance covered upstream in 8 hrs 48 min = Distance covered downstream in 4 hrs.

 x x 8 4 = (y x 4) 5

 44 x =4y 5

 y = 11 x. 5

 Required ratio = y + x : y - x 2 2

 = 16x x 1 : 6x x 1 5 2 5 2

 = 8 : 3 5 5

= 8 : 3.

Discussion:
107 comments Page 11 of 11.

Thanks Ashis.

Given is 8 hr 48min so converting min to hr

We have 48/60=4/5

I didn't understand how 8*4/5 will get.

As it is given to find out the ratio of speed of boat to speed of water w.r.to still water that is how required ratio is calculated.

You can find out from important formulae option i.e.

1/2(y-x)/1/2(y+x)
where y=speed at downstrem
x=speed at upstream.