A. 3.5km/hr
B. 5.75km/hr
C. 6.5km/hr
D. 7km/hr
Explanation:
Speed Downstream = 15.5 km/hr,
speed upstream = 8.5 km/hr
Speed of the stream = ½ (15.5 – 8.5)km = 3.5 km/hr
A. 13, 3
B. 12, 6
C. 15, 3
D. 14, 4
Explanation:
Let the speed of the man in still water and speed of stream be x kmph and y kmph respectively.
Given x + y = 18 — (1)
and x – y = 10 — (2)
From (1) & (2) 2x = 28 => x = 14, y = 4.
A. 15 kmph
B. 10 kmph
C. 12 kmph
D. 12.5 kmph
E. None of these
Explanation:
Let the speed of the man in still water be a kmph and let the speed of the stream be b kmph.
Now 30/(a + b) + 20/(a – b) = 4 and 45/(a + b) + 40/(a – b) = 7
Solving the equation, the speed of man in still water is 12.5 kmph.
A. 12 kmph
B. 13 kmph
C. 14 kmph
D. 15 kmph
Explanation:
The ratio of the times taken is 2:1.
The ratio of the speed of the boat in still water to the speed of the stream = (2+1)/(2-1) = 3/1 = 3:1
Speed of the stream = 42/3 = 14 kmph.
A. 20/6 hours
B. 27/2 hours
C. 30 hours
D. 30/13 hours
Explanation:
Speed downstream = 20 + 6 = 26 kmph.
Time required to cover 60 km downstream = d/s = 60/26 = 30/13 hours.
A. 5 kmph
B. 6 kmph
C. 7 kmph
D. 8 kmph
Explanation:
Speed downstream = d/t = 85/(2 1/2) = 34 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (34 – 18)/2 = 8 kmph
A. 70, 10 kmph
B. 35, 27 kmph
C. 50, 60 kmph
D. 45, 55 kmph
Explanation:
Speed of the boat in still water = (60+80)/2 = 70 kmph. Speed of the stream = (80-60)/2 = 10 kmph.
A. 35, 25 kmph
B. 80, 40 kmph
C. 40, 60 kmph
D. 50, 55 kmph
Explanation:
Speed downstream = 60 + 20 = 80 kmph
Speed upstream = 60 – 20 = 40 kmph
A. 6 kmph
B. 7 kmph
C. 8.5 kmph
D. 8 kmph
Explanation:
S = 1
M = x
DS = x + 1
US = x – 1
35/(x + 1) + 35/(x – 1) = 12
x = 6
A. 8 kmph
B. 4 kmph
C. 2 kmph
D. 10 kmph
Explanation:
M = 45
S = 1.5
DS = 6
US = 3
AS = (2 * 6 * 3) /9 = 4