SOLUTION: A hospital purchased 40 grams of a substance.Eight days later,when a doctor wanted to use some of the substance,he found that only 20 grams remained.Predict the amount remaining tw

Question 631377: A hospital purchased 40 grams of a substance.Eight days later,when a doctor wanted to use some of the substance,he found that only 20 grams remained.Predict the amount remaining two weeks after the purchase of the substance.(Please show the solution.)
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
This assumes that the substance is
decreasing at a linear rate ( straight line ).
The rate of decrease is

grams/day
----------------
Let grams of substance remaining =
Let = days since the purchase

is the grams present when , so

Two weeks after purchase is 14 days

There are 5 grams remaining after 2 weeks
Here's the plot:

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