Eleven adult chaperones will be needed
Answer: 
Step-by-step explanation:
Given: The total time taken by Evan to mow the 3 lawns = 
Time taken by Evan to mow the first lawn =
Time taken by Evan to mow the second lawn =
Now,Time taken by Evan to mow the third lawn =
⇒Time taken by Evan to mow the third lawn =
⇒Time taken by Evan to mow the third lawn =
Hence, the time taken by Evan to mow the third lawn = 
Answer:20
Step-by-step explanation:
17 + 3 = 20
20 + 3 = 23
The greatest common factor would be 16
Take into account, that in general, a cosine function of amplitude A, period T and vertical translation b, can be written as follow:

In the given case, you have:
A = 4
T = 3π/4
b = -3
By replacing you obtain:

Hence, the answer is:
f(x) = 4cos(8/3 x) - 3