Answer:
Step-by-step explanation:
There are two ways to write the relationship, hence two constants of proportionality.
d = kt
k = d/t = (2 mi)/(30 min) = 1/15 mi/min
t = kd
k = t/d = (30 min)/(2 mi) = 15 min/mi
__
As you can tell from the way the constants are computed, they are reciprocals of each other.