You must first attach the problems with your question.
Volume of this is 25920 inches cubed
The square root of 9 is 3
Answer:
The demabd function is:

Step-by-step explanation:
The demand follow the linear equation 
1. When p=$2.00 and q=9000, the equation is:

2. Whe p=$4.00 and q=0, the equation is:

3. Solve equation (1) for b:

4. Replace the value of b in equation (2)

The value of m is 4500
5. Calculate b, replacing m:

The value of b is 18000
The answer is 72
b/c 80% is equal to .80
so you do 90x.80