Dear Readers, Welcome to BOATS AND STREAMS - Aptitude Objective Questions have been designed specially to get you acquainted with the nature of questions you may encounter during your Job interview for the subject of BOATS AND STREAMS - Aptitude MCQs. These objective type BOATS AND STREAMS - Aptitude questions are very important for campus placement test and job interviews. As per my experience good interviewers hardly plan to ask any particular question during your Job interview and these model questions are asked in the online technical test and interview of many Banks, SSC, Railways, Postal and many Govt Jobs.
1. In water, the direction along the stream is called downstream. And, the direction against the stream is called upstream.
2. If the speed of a boat in still water is u km/ht and the speed of the stream is v km/hr, then :
Speed downstream = (u + v) km/hr
Speed upstream (u - v) km/hr.
3. If the speed downstream is a km/hr and the speed upstream is b km/hr, then :
Speed in strill water = 1/2 (a + b) km/hr
Rate of stream = 1/2 (a - b) km/hr
Explanation: Let the speed of the motorboat in still water be x kmph. Then,
Speed downstream = (x + 2) kmph; Speed upstream = (x - 2) kmph.
? 6/x+2 + 6/x-2 = 33/60
? 11x² - 240x - 44 = 0
? 11x² - 242x + 2x - 44 = 0
? (x - 22) (11x + 2) = 0 ? x = 22.
Hence, speed of motorboat in strill water = 22 kmph.
Explanation: Let man’s rate upsream be x kmph. Then, his rate downstream = 3x kmph.
? Rate in still water = 1/2(3x + x) kmph = 2x kmph.
So, 2x = 18 or x = 9.
? Rate upstream = 9 km/hr, Rate downstream = 27 km/hr.
Hence, rate of stream = 1/2(27 - 9) km/hr = 9 km/hr.
Explanation: Rate in still water = 1/2 (10 + 7) km/hr = 8.5 km/hr,
Rate of current = 1/2 (10 - 7) km/hr = 1.5 km/hr.
Rate upstream = (7/42)*60 kmh = 10 kmph. Speed of stream = 3 kmph.
Let speed in sttil water is x km/hr
Then, speed upstream = (x —3) km/hr.
x-3 = 10 or x = 13 kmph.
Speed in still water = (1/2) * (6 + 2) km/hr
= 4 km/hr