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−.316xpl us+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.