The time between seeing the lightning and hearing the thunder is s seconds. The distance d you are from lightning is approximately equal to one-fifth of s seconds. Which direct variation equation represents this situation?

The direct variation that can be established using the given parameters is that, the time it takes between seeing the lightning and hearing the thunder is directly related to the speed.

However, it can also be established that the time described above is inversely proportional to the distance. This can be written as,

t = k/d

We substitute the given expression for each of the known terms. t is time, s, and d is distance, 3s.

s = k/3s

The k written in the equation is the constant of proportionality.