The speed of a boat in still water is 15 kmph and the speed of the current is 3 kmph. The distance travelled by the boat from point A to point B downstream is 24 km more than the distance covered by the same boat from point B to point C upstream in the same time. How much time will the boat take to travel from point C to point B downstream ?

A) 2 hrs

B) 2 hrs 30 mins

C) 2 hrs 40 mins

D) 2 hrs 10 mins

Correct answer:
C) 2 hrs 40 mins

Description for Correct answer:
Rate downstream of boat = 15 + 3 = 18 kmph

Rate upstream of boat

= 15 - 3

= 12 kmph

Let, BC = x km

\( \Large \therefore \) AB = (x + 24) km

According to the question,

\( \Large \frac{x + 24}{18} = \frac{x}{12} \)

=> \( \Large \frac{x + 24}{3} = \frac{x}{2} \)

=> 3x = 2x + 48 => 3x - 2x = 48

=> x = 48 km

Time taken in rowing 48 km downstream = \( \Large \frac{48}{18} \ hours \)

= \( \Large \frac{8}{3} \ hours = 2 \ hours \frac{2}{3} \times 60 \ minutes \)

= 2 hours 40 minutes

Please provide the error details in above question

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