Question 51647: a pollution control device reduces the rate of emission of an air pollutanat in a car's exhaust by 56 ppm (parts per million) per hour. when the device is installed, it will take the car 10 h to emit the same amount of pollutant that it formerly did in 3h. what was the original rate of emmision of the pollutant in the car's exhaust?
Answer by josmiceli(19441)   (Show Source):
You can put this solution on YOUR website! When the device is installed, it will take the car 10 h to emit the same amount of pollutant that it formerly did in 3h.
How much pollutant gets emitted now as compared to before?
Let's say x amount got emitted in 3 hours
Set up the ratio x/3 , pollutants per hour
Now, the same amount, x, gets emitted in 10 hours
The ratio is x/10 polutants per hour
Set up a ratio of the ratios
(x/10) / (x/3) = pollutants per hour now / pollutants per hour before
(x/10) / (x/3) = 3 / 10
The pollutants per hour got REDUCED by 56 ppm per hour
p = rate before
p - 56 = rate now
3/10 = (p-56) / p
(3/10)p = p - 56
3p = 10p -560
7p = 560
p = 80 ppm per hour, rate before
p - 56 = 80 - 56
p - 56 = 24 ppm per hour, rate now
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