In the store, coffee of different varieties is sold. The table shows the mass of coffee packaging and its price. You need to buy 1 kg of coffee of one variety. How much will the cheapest purchase cost? Answer in rubles.

Solution:

To determine the cheapest purchase, we need to calculate the price per kilogram for each type of coffee.

• «Арабика» (Arabica):
  • Mass: 500 g = 0.5 kg
  • Price: 680 rubles
  • Price per kg: \( \frac{680 \text{ руб.}}{0.5 \text{ кг}} = 1360 \text{ руб./кг} \)
• «Кампания» (Kampaniya):
  • Mass: 100 g = 0.1 kg
  • Price: 160 rubles
  • Price per kg: \( \frac{160 \text{ руб.}}{0.1 \text{ кг}} = 1600 \text{ руб./кг} \)
• «Эгоист» (Egoist):
  • Mass: 250 g = 0.25 kg
  • Price: 325 rubles
  • Price per kg: \( \frac{325 \text{ руб.}}{0.25 \text{ кг}} = 1300 \text{ руб./кг} \)
• «Юлиус» (Julius):
  • Mass: 200 g = 0.2 kg
  • Price: 340 rubles
  • Price per kg: \( \frac{340 \text{ руб.}}{0.2 \text{ кг}} = 1700 \text{ руб./кг} \)

Comparing the prices per kilogram, the cheapest coffee is «Эгоист» at 1300 rubles per kilogram.

Ответ: 1300