The price of type a refrigerator sold in shopping malls is 2190 yuan per unit, and the daily power consumption is 1 degree, while the price of type B energy-saving refrigerator is 10% higher than that of type a refrigerator, but the daily power consumption is 0.55 degree? (calculated according to the service life of 10 years, 365 days per year and 0.40 yuan per kilowatt hour)
If a supermarket sells a refrigerator at a discount of X, it will be cost-effective for consumers to buy it. According to the question, it is 2190 × 10 + 365 × 10 × 1 × 0.4 ≤ 2190 × (1 + 10%) + 365 × 10 × 0.55 × 0.4, that is 219x + 1460 ≤ 2409 + 803. Solving this inequality, it is cost-effective for consumers to buy a refrigerator at least at a discount of 20%