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.

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

hi there!

first we need to find out how much they are adding to each number to make the next number.

ex: 4 + 4 = 8, 8 + 8 = 16, and so on.

so continuing with 32,

32 + 32 = 64

64 + 64 = 128

128 + 128 = 256

256 + 256 = 512

4, 8, 16, 32, 64, 128, 256, 512

the 8th term of the sequence will be 512

hope this ! ~