[填空题]
How many kWh of enerrztb:.8pn)tp o1 /vyzw8k oq 0nof- 5k vze )hp03j +mx9xr(tqgy does a 550-W toaster use in the morning if it is in operation for a tota9pez(h03vxt )mrx q+j l of 15 min? At a cost of $9.0\,cents/kWh$, estimate how much this would add to your monthly electric energy bill if you made toast four mornings per week.
energy $\approx$ kWh
cost $\approx$ cents/mouth
