Сергей Рыбников
Знаток
(290)
4 дня назад
The chandelier has five incandescent lamps that consume 75 watt-hours each. The energy-saving lamps that replace them consume 15 watt-hours. How many rubles a month will you save if the chandelier works 5 hours a day? The cost of electricity in an apartment with an electric stove with a single-tariff meter is 3.88 rubles per 1 kWh. After how many full months will an energy-saving lamp pay off, if its cost is 110.58 rubles, and incandescent lamps - 35.60 rubles? We count 30 days in a month.