Multiple choice

Emma intends to row down a river and back. The one-way distance is 7 miles. The current flows at 2 miles per hour, while Emma rows at a constant speed of 5 miles per hour in the still water. How long does it take for Emma to row downstream and then return upstream?

  1. 2 hours 20 minutes

  2. 3 hours 15 minutes

  3. 3 hours 20 minutes

  4. 4 hours 10 minutes

  5. 4 hours 20 minutes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Downstream speed = 5+2=7 mph. Time = 7/7 = 1 hour. Upstream speed = 5-2=3 mph. Time = 7/3 = 2 hours 20 minutes. Total time = 3 hours 20 minutes.

AI explanation

Using the boat and stream formula, the downstream speed is 5 plus 2, equaling 7 miles per hour, and the upstream speed is 5 minus 2, equaling 3 miles per hour. The downstream time is 7 divided by 7, which is 1 hour, and the upstream time is 7 divided by 3, which is 2.33 hours, or 2 hours and 20 minutes. Adding these times together gives a total duration of 3 hours and 20 minutes.

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