Velocity / Speed Related Q?

Question

According to a rule-of-thumb, every five seconds between a lighting flash and the following thunder gives the distance to the flash in mils. Assuming that the flash of light arrives in essentially no time at all, estimate the speed of sound in m/s from this rule.

* I have no idea what to do, plz include explanation.

Answer 1

The fact that there was virtually no time delay is extraneous and has no bearing on the OTHER fact, the rule of thumb, that sound travels at about 5 seconds per mile. The problem SAYS to estimate the speed of sound from the RULE. Now all you have to do is convert miles to meters and you are in business. 1 mile is about 1610 meters. Dividing 1610 meters by 5 means 322 meters, so the speed is about 322 meters per second.  

Answer 2

This is simply rate times time equals distance.

Every five seconds the sound travels a mile (the given information).  

So, rate x 5 seconds = 1 mile

rate =  1/5 mile /second

You'll have to convert that to meters / second yourself.

Answer 3

This means sounds travels one mile in 5 seconds. Just convert 1 mile to meters.

1 mi = 1609 m

then...

1609/5 = 322 m/s