1. During a particular summer, Dallas, Texas, endured 29 consecutive days on which the temperature was at least 110 oF. On many of those days, the combination of heat and humidity made it feel even hotter than it was. When the temperature is 100 oF, the apparent temperature A (or heat index) depends on the humidity h (expressed as a decimal) according to

A = 90.2 + 41.3h*

(a) For what humidity levels is the apparent temperature at least 110 oF? (This answer will be a closed interval. Why?)

(b) For what humidity levels is the apparent temperature less than 100 oF?

2. The combination of cold temperatures and wind speed determine what is called wind chill. The wind chill is a temperature that is the still-air equivalent of the combination of cold and wind. When the wind speed is 25 mph, the wind chill WC depends on the temperature t (in degrees Fahrenheit) according to

WC = 1.337t - 24.094

For what temperatures does it feel at least 30F colder than the air temperature? That is, find t such that WC ( t = 30?