Aptitude - Boats and Streams - Discussion

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

Downstream speed = a.
Upstream speed = b.

Stream speed = 1/2 (a-b)----Formula.
Boat speed = 1/2 (a+b)-----Formula.

Given boat speed = 13.
Stream speed = 4.

So 1/2(a+b)+1/2(a-b) = 13+4.

==> a=7.

Given D = 68km.

D = S*T.
Ta = D/Sa.

=>68/17.

=>4.

So time taken by the boat to go 68 km downstream is 4 hrs.

Boat -> a kmph& stream-> b kmph

A= boat speed at still water
B= water speed=rate of current=stream speed.

Along with the flow, Dss(downstream speed) = a+b,
Againist with the flow, Uss(upstream speed) = a-b.

So, a + b = 13 + 4 = 17,
Distance = 68 km,
Time = Dist/Uss,
T = 68/17 = 4hrs.

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).

Speed of boat in still water = 13km/hr.
Speed of the stream = 4km/hr.
Time taken by the boat to go 68 km downstream = ?

Speed of boat in downstream = (13+4)km/hr.
= 17km/hr.

Time = distance/speed.
= 68/17hr.
= 4hr.

Hi, please give me a solution for this question.

"A man can row 8 kms in still water. If in a river flowing at 2 km an hour, it takes him 24 minutes to row to a place and come back, how far of is this place?"

Since ship is going downstream,

Hence,
Resultant speed = 13 + 4 = 17 km/h.

Now,

Time = distance / speed.
==> Time = 68/17 = 4hours.

Therefore, the boat will take 4 hrs. To go 68 km downstream.

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.

Downstream speed = 13 + 4 = 17 km/hr.

Time = Distance/Downstream speed.
= 68 km/17 km/hr.

To simplify, divide both numerator and denominator by 17:
Time = 68 ÷ 17.
= 4 hours.

Answer: 4 hours.

Given:

Speed in still water U = 13 km/hr,

Speed of stream V = 4 km/hr,

Distance = 68 km,

Time = ?

Solution:

Time = distance / U+V(downstream speed)

=> 68/17,

=> 4 hour.