Answer: 19.4
Step-by-step explanation:
Given
Profit is given in terms of the selling price

to get the maximum price, differentiate y w.r.t x

Put
to get maximum value

Thus, the company must sell it at 19.4
Answer:
Estimation is just giving a general answer to the situation and can be specified on specifics depending on the numbers used and whichever question it's asking. But also remember that whenever you estimate your answer will be an approximate answers, not an exact.
Two angles are said to be complementary, if the sum of the measures of the to angles is equal to 90 degrees.
Thus, given that HFG is complementary to ACB, them mHFG + mACB = 90 degrees.
From the figure, given that the line from point F meats line CE at point P, then HFG = CFP.
But mCFE = 90 degrees and mCFE = mCFP + mPFE
Also PFE = DFH
Thus, mCFE = mCFP + mPFE = mHFG + mDFH = 90 degrees
Recall that mHFG + mACB = 90 degrees
Thus, mHFG + mACB = mHFG + mDFH
Therefore, mACB = mDFH.
The angle of depression is
tan^-1 3/7 = 23.2 deg