Nina can ride her bike 63,360 feet in 3,400 seconds, and Sophia can ride her bike 10 miles in 1 hour. What is Nina's rate in miles per hour if there are 5,280 feet in a mile?

First convert Nina’s distance to miles: 63,360 ÷ 5,280 = 12 miles. Convert 3,400 seconds to hours: 3,400 ÷ 3,600 = 17/18 hour. Her rate is 12 ÷ (17/18) = 216/17 ≈ 12.7 miles per hour, so the correct choice is 12.7 mph.

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