I don't understand this question, could someone solve/walk me through this?

One afternoon in Fort Simpson, Northwest Territories, the air temperature was −10ºC and the wind speed was 25 km/h. The air temperature dropped by 5ºC in the evening, but the wind chill did not change. What was the change in the wind speed from the afternoon to the evening? (use a wind chill chart if it helps you)

Sorry about the Chinese, the Chinese words are Celsius.

To answer this question, we need to understand the concept of wind chill and how it is calculated. Wind chill is the perceived decrease in air temperature felt by the human body due to the combination of actual air temperature and wind speed.

The wind chill chart takes into account both the air temperature and the wind speed to determine the perceived temperature. By referring to the wind chill chart, we can find out the wind chill for a given set of temperature and wind speed.

In this question, we are given that the air temperature in the afternoon was -10ºC and the wind speed was 25 km/h. We need to find the change in the wind speed from the afternoon to the evening, given that the air temperature dropped by 5ºC, but the wind chill did not change.

To solve this, we need to compare the wind chill values for the afternoon and the evening. Since the wind chill did not change, it means that the perceived temperature remained the same.

First, let's find the wind chill at -10ºC and the wind speed of 25 km/h using the wind chill chart. Looking at the chart, we can find that the wind chill at -10ºC and 25 km/h is -19ºC.

Next, we need to find the wind chill in the evening. The air temperature dropped by 5ºC, so the new air temperature is -15ºC. However, the wind chill did not change, so we know that the wind chill at -15ºC is also -19ºC.

By referring to the same wind chill chart, we need to find the wind speed that corresponds to a wind chill of -19ºC for an air temperature of -15ºC.

Depending on the specific wind chill chart you are using, find the row that matches -15ºC and then go across it until you find the column that matches -19ºC. The value in that cell will give you the wind speed needed to have a wind chill of -19ºC at -15ºC.

Once you have found the wind speed for -15ºC and -19ºC, subtract the initial wind speed of 25 km/h from this value to find the change in wind speed.

Please note that the wind chill chart values may vary depending on the specific chart you are using, so make sure to refer to a trusted source.