the initial temperature at 6 a.m is 20.4 degrees Fahrenheit
The temperature drops 2.1 degrees Fahrenheit per hour.
the number of hours from 6 am to noon is 6
so the remaining temperature is
= 20.4 - (2.1* 6)
= 20.4 - 12.6 = 7.8 degree Fahrenheit.
So the temperature at noon is 7.8 degrees Fahrenheit.