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A man can row upstream at 10 km/hr and downstream at 16 km/hr. Find the man’s rate in still water and the rate of current.
Explanation:
man’s rate in still water = 1/2 (16+10)
A boat can row at 16 km/hr in still water and the speed of river is 10 km/hr. Find the speed of boat with the river and speed of boat against the river.
Speed with the river (downstream) = 16+10
Speed against the river (upstream) = 16-10
A man goes downstream 60 km and upstream 20 km, taking 4 hrs each. What is the velocity of current?
Downstream speed = 60/4 = 15 km/hr
Upstream speed = 20/4 = 5 km/hr
Velocity of stream = (15-5)/2 = 5 km/hr
A man rows downstream 28 km and upstream 16 km, taking 5 hrs each time. What is the velocity of current?
A man can row 30 km upstream and 44 km downstream in 10 hrs. Also, he can row 40 km upstream and 55 km downstream in 13 hrs. Find the speed of the man in still water.
Let upstream speed = x, downstream speed = y km/hr
Then, 30/x + 44/y = 10 and 40/x + 55/y = 13
Put 1/x = a, 1/y = b
Solve the equations.
A = 1/5, b = 1/11
So, x = 5, y = 11
Speed in still water = (5+11)/2 = 8
A man can row 24 km upstream and 36 km downstream in 6 hrs. Also, he can row 36 km upstream and 24 km downstream in 6.5 hrs. Find the speed of the current.
A man can row 6 km/hr in still water. When the river is running at 2 km/hr, it takes him 1 ½ hr to row to a place and come back. How far is the place?
B is speed of boat in still water, R is speed of stream
Time is total time taken for upstream and downstream
Distance = time * [B^2 – R^2] / 2*B
=3/2 * [6^2 – 2^2] / 2*6
In a stream running at 2 km/hr, a motorboat goes 10 km upstream and back again to the starting point in 55 minutes. Find the speed (km/hr) of the motorboat in still water.
10 =55/60 * [B^2 – 2^2] / 2*B
A man can row a certain distance downstream in 2 hours and return the same distance in 6 hours. If the speed of current is 22 km/hr, find the speed of man in still water.
Use:
B = [tu + td] / [tu – td] * R
B = [6+2] / [6-2] * 22
B = 44
A man can row 9 3/5 km/hr in still water and he finds that it takes him twice as much time to row up than as to row down the same distance in river. The speed (km/hr) of the current is.
Let downstream time = t, then upstream time = 2t
48/5 = [2t+t] / [2t-t] * R
A boat can travel 4.2km upstream in 14min. If the ratio of the speed of the boat in still water to the speed of the stream is 7:1. How much time will the boat take to cover 17.6km downstream ?
Explanation :
Speed = 7x:x
Downstream = 8x; upstream = 6x
Upstream speed = 4.2*60/14 = 18kmph
6x = 18
X = 3
Downstream = 8*3 = 24
Time taken for 17.6km = 17.6*60/24 = 44min
A man can row at 4 kmph in still water. If the velocity of the current is 1 kmph and it takes him 1 hour to row to a place and come back. how far is that place.
Let the distance is x km
Rate downstream = 4 + 1 = 5 kmph
Rate upstream = 4 – 1 = 3 kmph
then
x/5 + x/3 = 1
3x + 5x = 15
x = 15/8 = 1.8 km
Arun takes thrice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat in still water and stream is.
speed downstream = x kmph
Speed upstream = 3x kmph
(3x+x)/2 : (3x-x)/2
4x/2 : 2x/2 = 2:1
A boat takes 120min less to travel 30km downstream than to travel the same distance upstream.If the speed of the boat in still water is 8kmph then the speed of the stream is.
Speed of the stream = x
(30/8-x) – (30/8+x)= 120/60 = 2/1
30(8+x) – 30(8-x) = 2[64 – x2] 240+30x-240x+30x = 2[64 – x2] 60x = 128- 2x2
2x2+60x-128 = 0
x2+30x-64 = 0
(x+32)(x-2) = 0
X=2kmph
A boat running downstream covers a distance of 24km in 4hrs, while for covering the same distance upstream it takes 6hrs, what is the speed of the boat in still water ?
24/x-y = 6
6x – 6y = 24………….(1)
24/x+y = 4
4x+4y = 24………….(2)
24x – 24y = 96
24x+24y = 144
Solve abv 2 equ
48x = 240
X = 240/48 = 5
A man swims downstream 40 km in 5 hours and upstream 24 km in 2 hours. Find his speed in still water ?
Downstream = 40/5= 8 kmph
Upstream = 24/2== 12 kmph
Speed in still water = 1/2 ( 8+12) = 10 kmph
The speed of a boat in still water in 12 km/hr and the rate of current is 4 km/hr. The distance travelled downstream in 12 minutes is.
Speed downstream = (12 + 4) kmph = 16 kmph.
Distance travelled = 16 x12/60 km = 3.2 km
A boatman goes 2 km against the current of the stream in 1 hour and goes 1 km along the current in 10 minutes. How long will it take to go 5 km in stationary water?
downstream =(1x 60)/10 = 6 kmph
Rate upstream = 2 km/hr.
Speed in still water =(6 + 2) /2= 4 kmph
time = 5/4 = 1.25hrs
A boat goes 24 km upstream and 28 km downstream in 6 hours. It goes 30km upstream and 21 km downstream in 6 hours and 30 minutes. The speed of the boat in still water is.
speed of the boat in still water = x kmph
speed of the current = y kmph
upstream speed = (x – y) kmph
downstream speed = (x + y)kmph
24/(x-y) + 28/(x+y) = 6
30/(x-y) + 21(x+y) = 13/2
X = 10kmph
A boat takes 30 hours for travelling downstream from point A to point B and coming back to point C midway between A and B. If the velocity of the stream is 2 kmph and the speed of the boat in still water is 15 kmph, what is the distance between A and B?
velocity of the stream = 2 kmph
Speed of the boat in still water is 15 kmph
Speed downstream = (15+2) = 17 kmph
Speed upstream = (15-2) = 13 kmph
Let the distance between A and B be x km
x/17+(x/2)/13=30
x/17+x/26=30
43x/442=30
x=30*442/43 = 308.37 = 308km
distance between A and B = 308 km
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