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
Answer is 175
To start you need to work backwards from the mean so do 158*4 to give you the total of the revenue then simply minus what was given to get 175
Hope this helped
The weight is proportional to the price. So if 10lb cost $18.24, quarter as much (2.5lb) would cost four times less($18.24÷4=$4.56).