(1 + c)/(r + e + c). The money multiplier (also called the credit multiplier or the deposit multiplier) is a measure of the extent to which the creation of money in the banking system causes the growth in the money supply to exceed growth in the monetary base.
A buzzing light switch could mean the fixture is wearing out, causing an arc of electricity behind the wall plate. If this is the case, the potential for an electrical fire may exist.
Re: LED's glow when off It's the light switch. Some let through a few milliamps - nothing you'd notice with a normal light. Also, the driver getting the voltage right can have a capacitor that discharges very slowly through the LEDs. I think the first is more likely for 5mm LEDs and the second for power LEDs.