Answer:
The exposure time that equals 750 is 3.4 hr
Explanation:
The given formula is:
[tex][tex]T=.0002*x^{2} -.316*x+127.9[/tex][/tex]
In the formula:
T= exposure time
x= carbon monoxide present in ppm
So, to calculate the exposure time when carbon monoxide is 750ppm, you should replace the "x" by 750.
[tex][tex]T=.0002*750^{2} -.316*750+127.9[/tex][/tex]
T=3.4hr