Recent questions tagged streams

Description : A motorboat running upstream takes 4 hrs 24 mins to cover a certain distance, while it takes 2hrs to cover the same distance running downstream. What is the ratio between the speed of the boat and speed of the water current respectively? A) 8:3 B) 5:2 C) 3:7 D) 2:4

Last Answer : ANSWER : A Explanation: Let the man's rate upstream be x'km/hr and downstream be y'km/hr Then distance covered upstream by 4hrs 24mints = distance covered by downstream in 2hrs (x * 4 2/5) = y *2 22x/5 = 2y Y = ... = (y+x/2) : (y -x/2) = 16x/10 : 6x/10 = 16x : 6x = 8:3

Description : Mohana can row 80km upstream and 110km downstream in 26 hrs. Also she can 60km upstream and 88km downstream in 20 hrs. Find the speed of the girl in still water and the speed of the current in ratio: A) 5:6 B) 3:6 C) 7:9 D) 8:3 

Last Answer : ANSWER : D Explanation: Let rate upstream = x' km/hr and  Rate downstream = y' km/hr  Then 80/x + 110/y = 26 ---1  60/x + 88/y = 20--2  By solving 1 and 2  y= 11 ; x = 5  Rain in still water ... 5) km/hr = 8 km/hr  Rain of current = ½ (11 - 50) km/hr = 3 km/hr  The required answer is 8:3

Description : There are 3 poles M, N and O in a straight line such that point N is equidistant from points M and O. A boat can travel from point M to O downstream in 6 hours and from N to M upstream in 4 hours. Find the ratio of boat in still water to speed of stream. A) 2:3 B) 7:1 C) 3:2 D) 1:7

Last Answer : ANSWER: B Explanation: Let speed in still water = x km/hr, of current = y km/hr Downstream speed = (x+y) km/hr Upstream speed = (x - y) km/hr Let MO = 2p km. So MN = NO = p km.  So 2p/(x+y) = 6 --------1  p/ ... - 2y) = 6x + 6y  8x - 8y = 6x +6y  2x = 14y  x/y = 14 / 2 = 7/1  x : y = 7 :1

Description : A motorboat can cover 80 km upstream and 120 km downstream together in 26 hours. Also it can cover 100 km upstream and 144 km downstream together in 32 hours. What is the speed of the motorboat in still water? A) 12 km/hr B) 15km/hr C) 8.5km/hr D) 19km/hr 

Last Answer : ANSWER :C Explanation:  Upstream speed in both cases is 80 and 100.  Ratio is 80 : 100 = 8:10 = 4 : 5.  So let times in both cases be 4x and 5x  Downstream speed in both cases is 120 and 144 resp.  Ratio is ... 12 km/hr  So speed of boat = 1/2 * (5+12) =17/2km/hr  speed of boat = 8.5 km/hr

Description : X, Y , Z are three towns on a lake which flows uniformly. Y is equidistant from X and Z. A man rows from X to Y and returns in 20hrs. He can row from X to Z in 8 hr. The ratio of speed of the man in still water to the speed of the current is. A) 3:5 B) 5:3 C) 2:3 D) None of these

Last Answer : ANSWER: A Explanation: Let the speed of man in still water = x km/hr Speed of the current = y km/hr Speed of downstream = (x+ y) km/hr Speed of upstream = ( x - y) km/hr Let the lake be flowing from X to Z and  xy = yz a ... y = 1 / 4  4x - 4y = x + y  3x = 5y x / y = 3 / 5 x : y = 3 : 5

Description : Dhanvanth can swim at 15 km/hr in stagnant water. In a river with 3 km/hr current, he swims to a certain distance and comes back within 100 min. What is the distance between the two points? A) 11km B) 13km C) 19km D) 12km

Last Answer : ANSWER: D Explanation: Speed in still water (a) = 15 km/hr Speed in current( b) = 3 km/hr Upstream speed = a - b = 15 - 3 = 12 km/hr Downstream speed = a + b = 15 + 3 = 18 km/hr Let the ... 36 = 5 / 3 15x = 36 * 5 x = 36 * 5 / 15 = 12 km Distance between the two points is 12km

Description : A boys rows to a certain place and comes back, but by mistake he covers 2/3rd more distance while coming back. The total time for this journey is 20 hours. The ratio of speed of boat to that of ... starting point from his present position? A) 2hr 13mints B)1hr 30 mins C) 2hr 30mins D)1hr 40 mins

Last Answer : ANSWER : A Explanation: let speed of boat and stream be 2x and x respectively So downstream speed = 2x+x = 3x, and upstream speed = 2x-x = x Let total distance between points is d km So he covered d ... with speed 3x = 48 km/hr(downstream) So time is 80/36 * 60 = 133.33 minutes = 2hr 13mins

Description : A man goes 4km upstream of the stream in 2hr and goes 2km downstream of the stream in 20mints. How long will it take to go 10km in stationary water? A) 1hr 15mits B) 2hrs 30mints C) 5hrs 30mints D) 3hrs 45mints

Last Answer : ANSWER : B Explanation:  Rate downstream = (2/20 * 60) km/hr  = 6 km/hr  Rate upstream = 2 km/hr  Speed in still water = ½(6+2)km/hr  = 4 km/hr  Required time = distance / speed  = (10/4) hrs =(5/2)hrs =2 ½ hrs = 2hrs 30mits.

Description : Faucet 'P' can fill the tank completely in12 hrs while faucet'q' can empty it by 24 hrs. By mistake, Anitha forgot to close the faucet q', As a result, both the faucet remained open. After 8 hrs, faucet realized the ... '. In how much time now onwards, would the tank be full? A) 4 B) 8 C) 12 D) 16 

Last Answer : Answer: B Explanation: Faucet P can fill the tank completely in 12 hours => In 1 hour, Faucet P can fill 1/12of the tank Faucet q can empty the tank completely in 24 hours => In 1 hour, Faucet q can empty ... tank. Time taken to fill the remaining (1−1/3)=2/3of the tank =(2/3)/(1/12) = 8 hours

Description : A motor boat sails 30 km of a river towards upstream in 10hrs. How long will it take to cover the same distance downstream, if the speed of the current is ½ of the speed of the boat in still water. A) 1.8hrs B) 3.33hrs C) 5hrs D) None of these

Last Answer : ANSWER : B  Explanation:  Upstream speed = x –y  Downstream speed = x + y  x– y = 30/10 = 3km/hr  Again x = 2y  Therefore x – y = 3  y= 3km/hr ; x = 6km/hr  Therefore x + y = 9 km/hr  Time during downstream = 30/9 = 3.33hrs

Description :  Sakthi rows a boat at 4 km upstream in 1hour and 1 km downstream in 20 minutes. How long will he take to reach 3.5km in still water? A) 1 B) 2 C) 3 D) 4

Last Answer : ANSWER:A Explanation: Upstream Speed = 4/1 = 4km/hr Downstream Speed = 1/20 = 0.05 km/min = 0.05*60 = 3 km/hr Hence, speed of boat = 1/2( Upstream Speed + Downstream Speed) = 1/2 (4+3 ... , the time required to reach the distance of 3.5 km=DistanceCovered/Speed of boat = 3.5/3.5km/hr =1 km/hr

Description : A boat man lakes 5hrs 30 mins to row a boat 30km downstream of a river and 4 hrs 15mints to cover a distance of 10km upstream. Find the speed of the river current in km/hr. A) 1.5 km/hr B) 3km/hr C) 5km/hr D) 7 km/hr

Last Answer : ANSWER: A  Explanation:  Rate downstream = (30 / 5 ½ ) km/hr  = 30 / (11/2) km/hr  = 30 * 2 / 11 km/hr = 60/11 km/hr  Rate upstream = (10 / 4 ¼)km/hr  = 10 / (17/4)km/hr  = 10 * 4 / 17 km/hr = ...  Speed of current = 1 / 2 (a - b) km/hr  =1 / 2 (60 / 11 - 40 / 17)  = 1.5 km/hr (approx.)

Description : A boat goes 3.5km upstream in 24 mins and the speed of the stream is 1.5km per hour, then the speed of the boat in still water is. A) 4.3 km/hr B) 7.4 km/hr C) 5.2km/hr D) 10.25km/hr

Last Answer : ANSWER: D  Explanation:  Speed of upstream = 3.5 / 24 km/min  = 3.5 / 24 * 60 km/hr = 8.75 km/hr  Speed of the stream = ½ (a - b)km/hr = 1.5 km/hr  1.5 = ½ ( a- 8.75)km/hr  a = 11.75 km/hr ... (a + b) km/hr  = ½ (11.75 + 8.75) = ½(20.5)  The speed of the boat in still water = 10.25 km/hr

Description : A man can row 4 km against the stream in 40mins and return in 36mins. Find the rate of current.  A) 1/2 km/hr B) 1/3 km/hr C) 2/3 km/hr D) 1/4 km/hr

Last Answer : ANSWER: B  Explanation:  Speed of the man (upstream) = (4 / 40 * 60) km/hr  = 6 km/hr  Speed of the man (downstream) = ( 4 / 36 * 60) km/hr  = (60 / 9)km/hr  = 20/3 km/h  Rate of the current = ½[downstream ... 6] km/hr  = ½ [ 20 - 18/3] km/hr  = ½ [2/3]km/hr Rate of the current = 1/3 km/hr

Description : A pedal boat can cover 20km in 1 hr in still water. And it takes thrice as much as time to cover up than as to cover down the same distance in running water. The speed of the current is. A) 7.5 km/hr B) 20 km/hr C) 5 km/hr D) 10 km/hr

Last Answer : ANSWER : D Explanation: Let the speed of upstream be x' km/hr Then speed in downstream = 3x km/hr[thrice as much as time to cover up than as to cover down the same distance in running water] Speed in ...  Speed in downstream = 30 km/hr  Hence speed of the current = (30 -10)/2  = 10 km/hr.

Description : A fisherman rows to a place 24km distance and back in 7 hours. He finds that he can row 2km with the stream in the same time 1.5 km against the stream.The rate of the stream is? A) 7 B) 5 C) 3 D) 1 

Last Answer : Answer: D  Explanation: Let be moves 2 km downstream in x Hours Then in speed downstream = 2/x kmph Speed in upstream = 1.5/x kmph ==> 24/2/X + 24/1.5/X = 7 12x+16x=7 Therefore x=1/4 Speed in downstream = 8 Kmph Speed in upstream = 6 Kmph Then the Rate of stream = 1/2 (8 - 6) = 1 Kmph

Description : A girl can row 15 kmph in still water and he finds that it takes him thrice as long to row up as to row down the river. Find the rate of stream. A) 2.5 B) 5.5 C) 7.5 D) 12.5 

Last Answer : Answer: C Explanation: Given that, time taken to travel upstream = 3 time taken to travel downstream When distance is constant, speed is inversely proportional to the time Hence, 3 speed upstream = speed downstream ... ., speed upstream =7. 5 km/hr Rate of stream =1/2(3x−x)= x = 7.5km/hr

Description : A woman rows to a place 24km distant and come back in 7 hrs. She finds that she can row 2km with the stream in the same time as 1.5km against the stream. The rate of the stream is, A) 2 B) 4 C) 1 D) 3

Last Answer : ANSWER: C  Explanation:  Suppose she move 2km downstream in x hrs  Then, speed of downstream = (2/x) km/hr  Speed of upstream = (1.5/x) km/hr  Therefore 24/(2/x) + 24/(1.5/x) = 7  12x + 16x = 7 ... of downstream = 8km/hr and upstream = 6km/hr  Rate of the stream = ½ (8 - 6 )km/hr  = 1 km/hr

Description : A boy rows 1500m in 1350 seconds against the stream and returns in 15 minutes. His rowing speed in still water is. A) 5km/hr B) 4km/hr C) 7km/hr D) 9km/hr

Last Answer : ANSWER : A  Explanation:  Rate upstream = (1500 / 1350) m/s = (150/135) m/s = 10/9 m/s  Rate downstream = (1500 / 900)m/s = (15/9)m/s  = 5/3 m/s  Rate in still water = ½ [ a+ b]  = ½[10 / 9 + 5 /3 ... +15 / 9]  = ½[25/9]  = 25/18 m/s  = (25/18) * (18/5)km/hr  speed in still water = 5km/hr

Description : A mototboat can row to a place 112 km away and come back in 44 hours. The time to row 42 km with the stream is same as the time to row 24 km against the stream. Find the speed of boat in still water. A) 5.5 km/hr B) 7.5km/hr C) 10.5 km/hr D) 3.5 km/hr 

Last Answer : ANSWER: A Explanation: Downstream speed = 42/x km/hr Upstream speed = 24/x km/hr 112 / (42 / x) + 112 / (24 / x) = 44 112[x /42 + x / 24] = 44 112 / 3 [x / 14 + x / 8] = 44 11x / 56 = 44 * ... = 4 km/hr Speed of boat = 1/2 * (7 + 4) km/hr = 11 /2 speed of boat in still water = 5.5 km/hr

Description : A boatman can take the same time to row6.5km downstream and 3.5km upstream. His speed in still water 2.5 km/hr. The speed of the stream is. A) 0.75 km/hr B) 2.5 km/hr C) 1.5km/hr D) 7.5km/hr

Last Answer : ANSWER: A Explanation: Given that the speed in still water = 2.5 km/hr Let the speed of the stream be x; km/hr speed in upstream = (2.5 - x)km/hr Then time taken to cover 6.5 km downstream = 6.5 / (2.5+x) ... 5x = 8.75 + 3.5x 10 x = 7.5 x = 0.75 km/hr The speed of the stream is 0.75 km/hr

Description : A pedal boat goes 12km upstream and 14km downstream in 3hrs. It goes 15km upstream and 10.5km downstream in 3 hrs 15mints. The speed of the boat in still water is A) 10 B) 15 C) 20 D) 25 

Last Answer : ANSWER: A

Description : If a boy rows 8 km downstream in 6 hours and 4 km upstream in 4 hours then how long will he take to cover 16 km in stationary (still) water? A) 8 B) 14 C) 22 D) 16 

Last Answer : Answer: B Explanation: Distance covered in downstream = 8 km Time taken in downstream = 6 hours. Rate of downstream = 8/6=4/3 km/hr Distance covered in upstream = 4 km Time taken in upstream = 4hours. ... 3+1) = 7/6km/hr Time Taken to cover 16 km in still water = 16*6/7=14hrs (approximately)

Description : A boat takes 24 hours to cover 128 km downstream and 16 hours to cover 64 km upstream. Then the speed of the boat in still water is: A) 14/3 B) 8/7 C) 3/2 D) 9/5

Last Answer : Answer: A Explanation: Distance covered in downstream = 128km Time taken in downstream = 24 hours. Rate of downstream = distance / time = a = 128 km /24 hours = 16/3km/hr Distance covered in upstream = 64km Time taken in upstream ... / 2 = (1/2)(16/3+4) km/hr = (1/2)(28/3)km/hr = 14/3km/hr.

Description : Thanu can travel 24 miles downstream in a certain river in 12hrs less than it takes him to travel the same distance upstream. But if he could double his usual rowing rate for his 48 mile round trip, the downstream 24 miles would ... 3 miles/hr B) 8 / 3 miles/hr C) 7 / 5 miles/hr D) 3 / 5 miles/hr 

Last Answer : ANSWER : B 

Description : At the same speed a boat travelling 50km upstream and 78km downstream in 16hrs. Also it can travel 70km upstream and 104km downstream, in 22hrs at the same speed of the stream is. A) 5km/hr B) 3km/hr C) 4km/hr D) 2km/hr

Last Answer : ANSWER : C

Description : A boat covers 12 km upstream and 18km downstream in 3hrs while it covers 18 km upstream and 12km downstream in 3 ¼ hrs the velocity of the the boat upstream and downstream? A) 4,8 B) 8,12 C) 12,16 D) 3,9 

Last Answer : ANSWER : B 

Description : There is a bridge besides a river. Two friends Arun and varun started their journey from place L, moved to the garden located at another place M & then returned to place L. Arun moves by swimming at a speed of 30 ... 12km/hr, what will be the average speed of boat sailor? A) 36 B) 18 C) 24 D) 48 

Last Answer : ANSWER:B Explanation: As Arun swims both the ways at the speed of 30km/hr, the average speed of swimming is 30 km/hr Being a boat sailor, varun moves downstream at speed =24 +12=36km/hr and upstream at speed = 24-12= ... Upstream Speed])] = (36*12)/0.5(36+12) km/hr = 432/24 km/hr = 18 km/hr

Description : A boat takes 27 hrs to travel a distance upstream and takes 9hrs to travel the same distance downstream. If the speed of the boat in still water is 12km/hr, then what is the velocity of the stream? A) 8km/hr B) 6km/hr C) 4km/hr D) None of these

Last Answer : ANSWER : B  Explanation: Let the velocity of the stream be ‘ y’ km/hr Then the speed of the downstream = (12 + y)km/hr The speed of the upstream = (12 – y)km/hr 9 (12 + y) = 27 (12 – y) 108 + 9y = 324 – 27y 27y + 9y = 324 - 108 36y = 216 y = 6 km/hr

Description : A boat takes 38 hrs for travelling downstream from point p to point q and coming back to a point r midway between p and q. If the velocity of the stream is 8 km/hr and the speed of the boat in still water is 28 km/hr. What is the distance between p and q? A) 720 B) 640 C) 510 D) 450

Last Answer : ANSWER: A Explanation: Speed downstream = (28 + 8)km/hr = 36 km/hr Speed upstream = (28 – 8)km/hr = 20 km/hr Let the distance between p and q be ‘x’km Then, x/36 + (x/2)/20 = 38 x/36 +x/40 = 38 19x = 13680 X = 720 km Therefore the distance between p and q is 720km