The cellular determinants of K+ secretion in the principal cell include the intracellular K+ concentration, the luminal K+ concentration, the potential (voltage) difference across the luminal membrane, and the permeability of the luminal membrane for K+.
The average cost for a brake pad replacement, resurface rotors is between $254 to $361. Labor costs are estimated between $182 to $231 while parts are priced between $72 to $130.
The rear brakes will last twice as long as the front, since the front do most of the stopping power. So, $65 for brake pads, $10 for misc cleaner etc. and 2-2.5 hours for the repair labor is what you really should be paying for in your case. Each car is slightly different, so if you have a BMW the price is going to be double!