Answer: the temperature drop from day to night in the city is 31°C.
Explanation:
o calculate the temperature drop from day to night, we need to find the difference between the average daily high temperature and the average nightly low temperature.
Temperature drop = Average daily high temperature - Average nightly low temperature
Temperature drop = (-9°C) - (-40°C)
Temperature drop = -9°C + 40°C
Temperature drop = 31°C