Wind chill is a measure of how cold people feel when exposed to wind outside. A good estimate for wind chill can be found using this calculation:
(wind chill) = (air temperature) - 0.7 (wind speed),
where temperature is measured in degrees Fahrenheit (F) and the wind speed is measured in miles per hour (mph). Suppose the air temperature is F and the wind speed is mph. Which of the following is closest to the approximate wind chill?
7
9
11
13
15
