- #1

- 471

- 0

## Homework Statement

The cost of electricity varies widely throughout the United States; $0.120/kWh is a typical value. At this unit price, calculate the cost of (a) leaving a 40 W porch light on for 2 weeks while you are on vacation, (b) making a piece of dark toast in 3 min with a 970 W toaster, and (c) drying a load of clothes in 40 min in a 5200 W dryer.

## The Attempt at a Solution

I have my attempt but I doubt I doing this right because it doesn't make sense at all. Can you please tell me where I'm messing up? Thanks in adv.!

[tex]a) 40W*\frac{1kW}{1000W} = 0.04 kW[/tex]

[tex] 2 weeks * \frac{7days}{1week}*\frac{24 hours}{1 day}=336h[/tex]

[tex] \frac{0.120}{kWh}*0.04kW*336h= 1.6128[/tex]

Is my method for (a) right? I got $1.6128 and it seems too little.. =[