first of all using the letter C for current is a really bad idea.
we know that the resistance is time dependent and thus the current will be also time dependent (Ohm's Law)
now all we have to do is use the given info:
A voltage V across a resistance R generates a current C = V/R. Suppose a constant voltage of 9 volts is put across a resistance that is decreasing at a rate of 0.3 ohms per second when the resistance is 4 ohms.
(a) At what rate is the current changing?
(b) Is the current increasing or decreasing?
ok so if someone could like do explain how to do this problem that would help alot, i think you have to use the derivative of t somewhere in there...please help thanks