Calculus
809 ppm/min\(\frac{80}{9}\)\(\text{ ppm/min}\)
4009 ppm/min\(\frac{400}{9}\)\(\text{ ppm/min}\)
803 ppm/min\(\frac{80}{3}\)\(\text{ ppm/min}\)
4003 ppm/min\(\frac{400}{3}\)\(\text{ ppm/min}\)