A lightning flash is seen in the sky and 9.0 s later the boom of the thunder is heard. The temperature of the?

Question

A lightning flash is seen in the sky and 9.0 s later the boom of the thunder is heard. The temperature of the air is 12°C.
(a) What is the speed of sound at that temperature? [Hint: Light is an electromagnetic wave that travels at a speed of 3.00 x10^8 m/s.]
m/s
(b) How far away is the lightning strike?
km

Answer 1

Wikipedia is your friend. Check out:
http://en.wikipedia.org/wiki/Speed_of_sound

to get the speed of sound. Then knowing the speed and the time, you can determine the distance.