A ferry crosses a 27-mile stretch of water in 1 hour 30 minutes. What is the ferry's average speed?
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Answer: B
Correct answer: 18 mph. Write the time as a decimal: 1 hour 30 minutes = 1.5 hours. Speed = distance ÷ time =
- A: This multiplies the distance by the time instead of dividing.
- B (correct): Dividing 27 miles by 1.5 hours gives 18 mph.
- C: This writes 1 hour 30 minutes as 1.3 hours instead of 1.5 hours.
- D: This rounds the time up to 2 hours before dividing.