Answer:
y'(t) = k(700,000-y(t)) k>0 is the constant of proportionality
y(0) =0
Step-by-step explanation:
(a.) Formulate a differential equation and initial condition for y(t) = the number of people who have heard the news t days after it has happened.
If we suppose that news spreads through a city of fixed size of 700,000 people at a time rate proportional to the number of people who have not heard the news that means
<em>dy/dt = k(700,000-y(t)) </em>where k is some constant of proportionality.
Since no one has heard the news at first, we have
<em>y(0) = 0 (initial condition)
</em>
We can then state the initial value problem as
y'(t) = k(700,000-y(t))
y(0) =0
Answer:
17
Step-by-step explanation:
Let us suppose two years ago my brother's age was x years
Then, my age was 3x
Three years from now, my brother's age will be (x +2+3) = (x+5) years
And my age will be (3x+2+3) = (3x+5) years
But it is given that i will be twice as old as my brother.
So, 2(x+5)= (3x+5)
or, x= 5 years
So my brother's present age is 5+2= 7 years
And my age is 5*3+2= 17 years
First find out how much one onion weighs so divide 0.75 by 3. This gets you 0.25. Now all you need to do is multiply the weight of one onion by 10, 0.25 x 10 = 2.5
Answer:
1. 2,160ft^3
2. multiply the total volume by 2.5
3. 5,400 BTUs
Step-by-step explanation:
hope this helps
1day=24 hours
10 days=240hours
60mins=1hr
30mins=1/2hr
total is 240hr+21hr+0.5hr=261.5hr
total is 261.5hr
