#### scadaman29325

##### Catching up and tripping all over myself.

I work as the utility billing supervisor of a small city.

A customer asked me a question that stumped me.

He has 2 electric meters, house and garage.

The house used 1000 kwh for $98.50.

The garage used 500 kwh for $53.50.

He asked why do I come up with a different cost per kwh?

I explain that you have to take away the "base fee" or "readiness to serve charge" of $8.50, then divide and you'll come up with the same cost per kwh.

He ask why.

I said 'because that's the way it works'.

He says 'why'.

.

.

.

What is a good explanation of the mathematical principles for this type of situation?