Answer:
Step-by-step explanation:
ignore the "at the instant the man is 30 feet away" part, set it as X and the man's shadow as Y.
Similar triangles so we can do .
Solve for it we get 44y = 6x
Differentiate relative to time t, we get 44y' = 6x'.
change in x (x') is equal to 5. And we get the answer y' = .
the ft/sec is the rate of which the length of the shadow is changing. add 5 to it for the rate of the tip of his shadow moving away from the tower.
Answer:
B: 11 minutes.
Step-by-step explanation:
So, we know that the machine prints at a constant rate.
After 3 minutes, the machine prints 108 posters.
So, let’s find the <em>unit rate. </em>We will divide the output over the input. So:
So, the unit rate of the machine is 36 posters per minute.
We can write an equation. If t represent the number of minutes and p represent the amount of posters, then:
Gives the amount of posters p and t minutes.
We want to know how long it will take Jeffrey to make 396 posters.
So, we can substitute 396 for p and solve for t. Hence:
Divide both sides by 36:
Therefore, it will take Jeffrey 11 minutes to make 396 posters.