Answer:
The amount of the contaminant removed during the first three hours will be 48.8 pounds.
Step-by-step explanation:
There, in a large tank of water, are initially 100 pounds of a contaminant.
Also given that the cleaning method removes 20% of the remaining contaminant each hour.
So, after the first hour, the amount of the contaminant will remain by
pounds.
Now, after the second hour, the amount of the contaminant will remain by
pounds.
Finally, after the third hour, the amount of the contaminant will remain by
pounds.
Therefore, the amount of the contaminant removed during the first three hours will be (100 - 51.2) = 48.8 pounds. (Answer)