Question

At the beginning of an experiment, there are 400 grams of contaminants. Each hour, three-fourths of the contaminants are filtered out.

Use the model to calculate the number of contaminants after the third hour of the experiment.

the answer is not 168.75 cause that is how much filtered/went away. I need to know how much is left after it was filtered.

Answer 1

After three hours of filtering out three-fourths of the contaminants each hour from an initial 400 grams, there will be 6.25 grams of contaminants remaining.

Step-by-step explanation:

To calculate the number of contaminants left after the third hour of the experiment when starting with 400 grams, and with three-fourths of the contaminants being filtered out each hour, you perform the following calculations:

After the first hour: 400 grams × (1 - ¾) = 400 grams × ¼ = 100 grams remaining.

After the second hour: 100 grams × (1 - ¾) = 100 grams × ¼ = 25 grams remaining.

After the third hour: 25 grams × (1 - ¾) = 25 grams × ¼ = 6.25 grams remaining.

Therefore, after three hours, there will be 6.25 grams of contaminants left.

Answer 2

18.75

Step-by-step explanation:

first hour: 400×(1/4) = 100

second hour: 100×(1/4) = 25

third hour: 25×(1/4) = 18.75

but i have to give credit to the first answerer, this is not my answer, though i know how to do it i dont know how to explain it properly.