The speed of light is 3.00x10^8m/s. How fast is this in mph? Use the conversion 1mile = 1610m.

Use the conversion factors: 1 mile = 1610 meters, 1 min = 60 seconds, 1 hour = 60 minutes. Using these factors,

(3.00 x 10^8 m/s) x (1 mile / 1610 meter) x (60 s / 1 min) x (60 min / 1 h)

= 6.7x10^8 mph

Therefore, the speed of light in mph is approximately 6.7x10^8 mph.