The speed of a motor - boat is that of the current of water as 36 : 5.The boat goes along with the current in 5 h 10 min. It will come back in -
Nithin K ? Nov 20 '2016 at 19:45
Answer is : 6 h 50 min
Explanation:
Let the speed of the motor boat = 36 kmph and
speed of current stream= 5 kmph.
The boat goes along with the current in 5 hours 10 minutes = \(\frac{31}{6} hour\)First We Need To Calculate upstream and downstream for above condition
Speed downstream = (36x+5x) = 41x kmph
Since distance = speed × time, we have
distance = \(41x \times \frac{31}{6} \) km. ..................(i)Speed upstream =(36x-5x) = 31x kmph
speed = 31x kmph .........................................(ii)Hence, time taken to come back
\(Time = \frac{distance}{speed}\)
\(= \frac{equation (i) }{ equation (ii)}\)
\(= \frac{41x \times \frac{31}{6}}{31x}\)
\(= \frac{41}{6} hours\)= 6 hours 50 minutes.
