An electric board determines its monthly bills for residenti

An electric board determines its monthly bills for residential customers by charging a base price of $15.00 plus an energy charge of 13.21 cents for each kilowatt-hour (kWh) used. Write an equation for the monthly charge y (in dollars) as a function of x, the number of kWh used.

Solution

base price = $ 15.00 ( fixed charge)

variable price $13.21/100 = $0.1321 per kWh

So, let x be the no. of kWh

So, y = fixed charge +variable charge

y = 15 +0.1321x