During the month of January, temperatures can decrease by 18° per week. If this happens, and the temperature on January 12th was 9°, what is the temperature on January 19th?
9 - 18 = -9
To find the temperature on January 19th, we need to calculate the change in temperature from January 12th to January 19th.
Given that the temperature decreases by 18° per week, we can calculate the change in temperature over the course of one week as -18° (since it's a decrease).
Since there are 7 days in a week, the change in temperature from January 12th to January 19th would be -18° multiplied by 7 days, which equals -126°.
To find the temperature on January 19th, we need to subtract the change in temperature from the initial temperature on January 12th.
Therefore, the temperature on January 19th would be 9° - 126° = -117°.
Hence, the temperature on January 19th is -117°.