When I was young, I was taught the following trick. Estimate the delay, in seconds, between seeing a flash of lighting and hearing the thunder. Then divide by 5 and the result is the distance in miles. a) What are the units of the "5" that I was taught to divide by? b) Calculate a more accurate (thought less convenient) value of the "5" in the rule, to two significant digits. (Use the SAME units a the original "5"!)