Expected speed: 400 m in 50 seconds Therefore, speed in m/sec = 8 m/sec Given: 1 mile =1609 meters 1 meter = 1/1609 miles 1 hour = 60 sec x 60 sec =3600 seconds 1 second = 1/3600 hour To convert meters to miles, we should multiply it by 1/1609 To convert seconds to hour, we should multiply it by 1/3600 Therefore, 8 m/sec = 8 x (1/1609) Ă· (1/3600) = (8 x 3600)/1609 =17.9 miles / hr