Wvaries directly with u and inversely with d, in your equation use k as the correct constant of proportionality

The equation is given as W varies directly with u and inversely with d, then the equation is written as:
W = k1u
here k2 is the proportionality constant.
and p = k2here k2 is the proportionality constant.
Thus, combining both equations we get, p = Kwhere K = K1*K2, is the proportionality constant.