Joe's toaster broke. He bought a toaster oven to replace it, telling his wife Annie that it is cheaper to make toast in the toaster oven than in the range's oven

Question

Toast takes 5 minutes to cook in the toaster oven while it takes only 3 minutes in the range's oven. Is Joe right or is Annie, who says they've wasted their money? Explain.

Answer 1

The toaster oven uses 1400 W, while the range uses 3200 W. The energy used to
cook toast in the toaster oven is 1400 W x 5 min x 1 h/60 min = 116.7 Wh. The range oven
uses 3200 W x 3 min x 1 h/60 min = 160 Wh. Clearly, Joe is correct. It costs less than 1
cent to toast toast in the toaster oven, while it costs 1.3 cents to toast toast in the range.
A typical toaster oven costs $50, so it will take 166 toastings to pay the toaster oven cost
back.