Reading
Task 1. Read and write the word in the sentence you hear.
Kazakhstan, a vast country of Central Asia, has a markedly continental climate,
with winters almost everywhere, while summers are warm in the north and definitely
hot in the south. There are no obstacles that could protect the country from cold air
masses of polar or Siberian origin, while in summer, hot winds from the Iranian deserts
can blow. In addition, because of the huge distance from the oceans, the Asian
continent cools down a lot in winter and heats up in summer, so, both the highest and
the lowest records are noticeable. In fact, in the north, the temperature can reach -50
°C in winter and 40 °C in summer, while in the south, it can go from -35 °C in winter to
45 °C in summer.
Write
Vonarne
х - процент снижения цены (х < 100)
у = х/100 - доля снижения цены (y < 1)
20 000 у - величина (в грн) первого снижения
20 000 - 20 000у = 20 000 (1 - у ) - цена после 1-го снижения
20 000 (1 - у)·у - повторное снижение в грн
20 000 (1 - у) - 20 000 (1 - у)·у =
= 20 000(1 - у - у + у²) =
= 20 000 (у² - 2у + 1) - цена после повторного снижения в грн
По условию цена после повторного снижения равна 12 800 грн
20 000 · (у² - 2у + 1) = 12 800
у² - 2у + 1 = 0,64
у² - 2у + 0,36 = 0
D = 4 - 1.44 = 2.56
√D = 1.6
у1 = 0,5(2 - 1,6) = 0,2 → х = 20%
у2 = 0,5 (2 + 1,6) = 1,8 (не подходит, так как больше 1)
ответ: каждый раз снижали цену на 20%
