High concentrations of carbon monoxide CO can cause coma and possible death. The time required for a person to reach a COHb level capable of causing a coma can be approximated by the quadratic model Tequals=.0002xsquared2minus−.316xplus+127.9, where T is the exposure time in hours necessary to reach this level and 500less than or equals≤xless than or equals≤800 is the amount of carbon monoxide present in the air in parts per million (ppm).
a) What is the exposure time when xequals=540540?
b) Estimate the concentration of CO necessary to produce a coma in 99 hr.