Kenny and Chris are walking down the road. They walk a distance of 250meters in 50 seconds. What was their average speed? (remember to choose the correct units!)

Ascientist notices that an oil slick floating on water when viewed from above has many different colors reflecting off the surface, making it look rainbow-like (an effect known as iridescence). she aims a spectrometer at a particular spot and measures the wavelength to be 750 nm (in air). the index of refraction of water is 1.3