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

T=.0002x^2 - .316x + 127.9 where T is the exposure time in hours necessary to reach this level and 500 ≤ x ≤ 800 is the amount of carbon monoxide present in the air in parts per million​ (ppm).

​a) What is the exposure time when x= 800?

​b) Estimate the concentration of CO necessary to produce a coma in

9 hr.

 May 13, 2017

(a) just substitute x=800 into the equation for T


(b) set T=9 and solve the quadratic to find possible values for x. If any value lies outside the range 500...800 then discard it for this exercise.


You have memorised a general formula for solving a quadratic, use it here.  😃

Here's a refresher: http://www.purplemath.com/modules/quadform.htm


🌝  🌚 🌛  🌜 🌃 

 May 14, 2017
edited by Badinage  May 14, 2017
edited by Badinage  May 14, 2017

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