BOAT AND STREAM QUESTION

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 HOURS 10 MINUTES. IT WILL COME BACK IN ?

 LET THE SPEED OF MOTOR BOAT BE 36x kmph, AND

SPEED OF CURRENT = 5x kmph

THE BOAT GOES ALONG WITH THE CURRENT IN 5 HOURS 10 MINUTES i. e. 31/6 HOURS

THEREFORE,

      DISTANCE = 31/6 * (36x + 5x)

= (41x * 31) / 6 km,

RATE UPSTREAM = 36x - 5x

= 31x kmph

THEREFORE,

        TIME TAKEN = (41x * 31/6) / 31x

=41/6 HOURS

OR 6 HOURS 50 MINUTES....

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