That's obviously entirely dependent on how fast you ride. A racer should be able to do it in about 2 minutes or slightly less. I can do it in about 3 minutes. A casual rider might be able to stretch it into 5-6 minutes.
A 6-minute mile is fast and long for an average American human being.
about 1,000 mile per hour, dude
I presume you mean how long will it take for a 12 miles bike ride. It depends on how fast you can bike, if it's uphill or downhill. The average is between 8-13 mph for most people to bike on a 10-speed on the whole. By that measurement, it could take 50-90 minutes or so on the average.
The average time it takes to complete a 6-mile bike ride is around 30 minutes, depending on the individual's speed and fitness level.
21.75 miles per hour
The average square mile of a city can vary widely depending on the city's population density and geographic size. Larger cities like New York City may have a higher average square mile due to their dense urban areas, while smaller cities may have a lower average square mile.
500,000
10
They have an "average" speed. Definitely not as fast as a Quarter horse at the Quarter mile, nor as fast as a Thoroughbred at the 1-1.5 mile range nor as fast as an Arabian over long distances. But, know there are always exceptions to the "average" rule.
A quarter mile in 10.6 seconds = about 85 mph average speed.
5 minutes, 30 seconds
A 14-minute mile equates to an average speed of 4.3 miles per hour.