In a race, the winner ran the 100-meter dash in a world record time of 12.2 seconds. What is this speed in miles per hour? [1 mile = 1.609 km]
A) 2.28 mph
B) 81.96 mph
C) 18.34 mph
D) 8.2 mph

Question

Quizplus · Accepted Answer

To convert meters per second to miles per hour, we first need to convert meters to kilometers and seconds to hours:
100 meters is equal to 0.1 kilometers (since 1 kilometer = 1000 meters), and 12.2 seconds is equal to 0.00339 hours (since 1 hour = 3600 seconds). 
So, the speed in kilometers per hour is:
0.1 km ÷ 0.00339 hours = 29.5 km/h
To convert kilometers per hour to miles per hour, we use the conversion factor of 1 mile = 1.609 km:
29.5 km/h ÷ 1.609 = 18.34 mph (rounded to two decimal places). Therefore, the best choice is C.

In a Race, the Winner Ran the 100-Meter Dash in a World