In the store, several types of coffee are sold in various packages and at different prices. The table shows the mass of each package and its price. Which coffee's kilogram costs the least? In the answer, write the name and cost of one kilogram of this coffee.

Analysis:

• To find the cheapest coffee per kilogram, we need to calculate the price per 100 grams for each type of coffee.
• Arabica: 300 RUB for 200g. Price per 100g = 300 / 2 = 150 RUB. Price per kg = 150 * 10 = 1500 RUB.
• Robusta: 350 RUB for 250g. Price per 100g = 350 / 2.5 = 140 RUB. Price per kg = 140 * 10 = 1400 RUB.
• Liberica: 490 RUB for 500g. Price per 100g = 490 / 5 = 98 RUB. Price per kg = 98 * 10 = 980 RUB.
• Santos: 380 RUB for 200g. Price per 100g = 380 / 2 = 190 RUB. Price per kg = 190 * 10 = 1900 RUB.
• Comparing the prices per kilogram: Arabica (1500 RUB), Robusta (1400 RUB), Liberica (980 RUB), Santos (1900 RUB).
• The cheapest coffee per kilogram is Liberica.

Answer: Liberica, 980 RUB/kg