At the 2008 Olympics the Jamaican runner Shelly Ann Fraser ran the 100. meter dash in world record time of 10.78 seconds. What is this speed in miles per hour? [1 mile = 1.609 km]

Question

Quizplus · Accepted Answer

First, we need to convert 100 meters to miles by dividing by 1609 (since 1 mile = 1609 km):

100 meters ÷ 1609 = 0.06214 miles

Next, we need to convert seconds to hours by dividing by 3600 (since 1 hour = 3600 seconds):

10.78 seconds ÷ 3600 = 0.00299 hours

Finally, we can calculate the speed in miles per hour by dividing the distance by the time:

0.06214 miles ÷ 0.00299 hours = 20.8 mph

Therefore, the answer is C, 20.8 mph.

At the 2008 Olympics the Jamaican Runner Shelly Ann Fraser