Suppose r1 is held constant at 10 ohms and that r2 is

Question

Question: If two electrical resistances, R1 and R2, are connected in parallel, their combined resistance, R, is given by

(1/ R) = (1/R₁) + (1/R₂)

Suppose R1 is held constant at 10 ohms, and that R2 is increasing at 2 ohms per minute when R2 is 20 ohms. How fast is R changing at that moment?