How do gamma rays differ from visible light

The difference between visible light and gamma rays is their frequency, energy and wavelength. All electromagnetic waves travel at the same speed, which is called the speed of light. ... Visible light has much lower energy and longer wavelengths than gamma radiation.

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form

blue light is scattered in different directions by the tiny molecules of air. blue is scattered more than other colours because it has a shorter distance to travel which results in smaller waves. this is why we see a blue sky most of the time.