Aptitude - Boats and Streams - Discussion

Speed(s) = boat speed(u) + stream speed(v) = 13 + 4 = 17km/h and distance = 68km;
We know that speed = distance/time.
But we have to find the time then,
Time = distance/speed.
Time = 68/17 = 4 hours.

thank you everyone for the explanation.

Ans:
D + U/2 = 13 km/h.
(x+4) + (x-4)/2 = 13.
X = 13.

The Speed of the boat is 13km/h.
The Speed of the stream is given 4km/h.

Now
Time taken by the boat to go 68 km downstream.
S = D/T (Boat speed +Stream speed).
T = D/S
= 13 + 4 = 17,
T = 68/17 = 4 Hour(Ans).

Distance = speed / time.
Then time = distace/ speed.
Speed = boat speed+stream speed.
Speed = 13+4=17 distance = 68.
D = 68/17 = 4hrs.

In this question, we have seen boat and steam both speeds are in one side so we have to include both speeds [13+4]=17 and distance is 68.

So, 68÷17 = 4hour.

13 + 4,
= 17.
68/17 = 4.

Thanks everyone for explaining the answer.

Relative speed = B + w = 15km/hr.
T = D/Relative speed,
T = 68/15=4hours.

In the question they given the data that

speed of boat 13 km/hr and speed of stream is 4 km/hr

and they asked us to solve the time taken by the boat in down stream for a distance of 68 kms.

we know as per the formula down stream means speed of boat + speed of stream

therefore,
down stream = 13+4=17 km/hr
as per the problem we got to find time taken by boat to travel a distance of 68km down stream.

we have formula that, time=distance/speed
=68/17
=4 hours

13+4 = 17km/hr,
For 1 hour he goes 17 km.
Then for 68 km he takes 4 hrs.