Answer:
dA/dt = k1(M-A) - k2(A)
Step-by-step explanation:
If M denote the total amount of the subject and A is the amount memorized, the amount that is left to be memorized is (M-A)
Then, we can write the sentence "the rate at which a subject is memorized is assumed to be proportional to the amount that is left to be memorized" as:
Rate Memorized = k1(M-A)
Where k1 is the constant of proportionality for the rate at which material is memorized.
At the same way, we can write the sentence: "the rate at which material is forgotten is proportional to the amount memorized" as:
Rate forgotten = k2(A)
Where k2 is the constant of proportionality for the rate at which material is forgotten.
Finally, the differential equation for the amount A(t) is equal to:
dA/dt = Rate Memorized - Rate Forgotten
dA/dt = k1(M-A) - k2(A)
Answer:
Average rate of change from day 2 to day 5 is $43.33/day.
Step-by-step explanation:
Sales on day 2 = 200
Sales on day 5 = 330
Rate of change = 
Answer:
16 fluid ounces
Step-by-step explanation:
Mario buys 8 containers of soup.
Each container has 18 fluid ounces.
In other words, there are a total of:

144 fluid ounces.
Each of the 9 people got the same amount of soup. In other words, divided equally, each person got:

16 fluid ounces of soup.
And we're done!