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.
Answer:
Step-by-step explanation:
<u>Linear Modeling</u>
Some events can be modeled as linear functions. If we are in a situation where a linear model is suitable, then we need two sample points to make the model and predict unknown behaviors.
The linear function can be expressed in the slope-intercept format:
For the problem at hand, we must pick the adequate variables according to the data provided.
The question states the charge for renting a car is a function of the mileage. It also provides two points from which we can build our model. Let's set the following variables:
c = the charge for renting a car in dollars
x = the distance driven by the businessman in miles
Representing the ordered pair as (x,c), we have the points: (150,79) and (65,63.70). Our model will be expressed as:
We must find the values of m and b with the data provided. Substituting the first point:
Substituting the second point:
Both equations form the following system:
Subtracting both equations:
Note the variable b was canceled out in the operation, leaving only the variable m to solve. Joining like terms:
Solving:
From the first equation
Solving for b:
The model for the problem is:
Now we need to calculate how many miles (x) could be driven for c=$100. From the equation above, substitute c=100
Solve for x:
Rounding to the closest integer:
