Answer:
Step-by-step explanation:
We know that the water purifier filters 1/3 kg of contaminant per hour, that can be expressed as
Where is time in hours.
Then, the problem states that Nana needs to purify water that has 1/2 kg of contaminants. In other words, the initial condition of the function is 1/2.
Uniting all these, we can express the situation as
Where is the contaminant remaining in kilograms.
The function has to have a subtraction, because the purifier does that, it subtract contaminant from the water.
Therefore, the function that modelates this situation is