Answer:
C.
Step-by-step explanation:
Answer:
9
Step-by-step explanation:
we know by definition that

so now we evaluate

and if we want to do an extra step

which works.
Answer:
Differential equation

Solution

Value of constant k=0.327 days^(-1)
The rumor reaches 80% at 8.48 days.
Step-by-step explanation:
We know
y(t): proportion of people that heard the rumor
y'(t)=ky(1-y), rate of spread of the rumor
Differential equation

Solving the differential equation

Initial conditions:

Value of constant k=0.327 days^(-1)
At what time the rumor reaches 80%?

The rumor reaches 80% at 8.48 days.
Add 11 to both sides:
-4=-2t
divide 2 by both sides
2=t
Hope it helps! Comment if you have any questions!