Answer:
Let x = # of commercials
y = # of movies
<u>System of Equations:</u>
x + y = 90
40x + 110y = 500
Step-by-step explanation:
We have to set our variables before we start solving. After setting the variables, we can set up the equations. If x = # of commercials and y = # of movies, then we can assume x + y = 90, as there have been a total of 90 commercials and movies played altogether. Then, we know that their worth is $500, so the price of all the commercials played and the price of all the movies played (which is 40x + 110y) sum to $500.
T = 5, so after 5 years
p(t) = t^3 - 14t^2 + 20t + 120
Take derivative to find minimum:
p’(t) = 3t^2 - 28t + 10
Factor to solve for t:
p’(t) = (3t - 2)(t - 5)
0 = (3t - 2)(t - 5)
0 = 3t - 2
2 = 3t
2/3 = t
Plug 2/3 into original equation, this is a maximum. We want the minimum:
0 = t - 5
5 = t
Plug back into original:
5^3 - 14(5)^2 + 20(5) + 120
125 - 14(25) + 100 + 120
125 - 350 + 220
- 225 + 220
p(5) = -5
Answer:
c
Step-by-step explanation:
