Multiple choice

A boat takes $2$ hours to travel $8 km$ and back in still water lake with water velocity of $4 km/h$, then the time taken for going upstream of $8 km$ and coming back is

  1. 120 min

  2. 160 min

  3. 200 min

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
AI explanation

The boat takes 2 hours to travel 8 km and back in still water, covering a total of 16 km, so its still water speed is 8 km/h. The upstream speed is reduced by the 4 km/h current to 4 km/h, and the downstream speed is increased to 12 km/h. The total time to go 8 km upstream and return is (8/4) + (8/12) hours, which equals 2 and 2/3 hours, or 160 minutes. The result is 160 min.

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