An inversely proportional equation for our set of circumstances looks like this: [tex]t= \frac{k}{r} [/tex]. We have a t value of 2 and an r value of 30, so we will sub those values in and solve for k, the constant of variation. [tex]2= \frac{k}{30} [/tex]. Multiply both sides by 30 to get that k = 60. Now we need to find t when r = 50. We can do this now because we have a value for k. [tex]t= \frac{60}{50} [/tex] and t = 1.2 hours.