A. Total Revenue (R) is equal to price per dive (P) multiplied by number of customers (C). We can write
.
Per price increase is $20. So four price increase is $
. Hence, price per dive is 100+80=$180.
Also per price increase, 2 customers are reduced from 30. For 4 price increases,
customers are reduced. Hence, total customers is
.
So Total Revenue is:

B. Each price increase is 20. So x price increase is 20x. Hence, new price per dive would be equal to the sum of 100 and 20x.
Also per price increase, customers decrease by 2. So per x price increases, the customer decrease is 2x. Hence, new number of customers is the difference of 30 and 2x.
Therefor we can write the quadratic equation for total revenue as the new price times the new number of customers.

C. We are looking for the point (x) at which the equation modeled in part (B) gives a maximum value of revenue (y). That x value is given as
, where a is the coefficient of
and b is the coefficient of x. So we have,

That means, the greatest revenue is achieved after 5 price increases. Each price increase was 20, so 5 price increase would be
. So the price that gives the greatest revenue is
.
ANSWERS:
A. $3960
B. 
C. $200
He practiced for 1 hour and 30 minutes
Answer:
43.68
Step-by-step explanation:
Answer:
x = 
Step-by-step explanation:
Given
-
=
← factor denominator
-
= 
[ x ≠ 0, x ≠ - 1 as these would make the terms undefined ]
Multiply through by x(x + 1)
4x² - 5(x + 1) = 4
4x² - 5x - 4 = 4 ( subtract 4 from both sides )
4x² - 5x - 9 = 0 ← in standard form
(x + 1)(4x - 9) = 0 ← in factored form
Equate each factor to zero and solve for x
x + 1 = 0 ⇒ x = - 1
4x - 9 = 0 ⇒ 4x = 9 ⇒ x = 
However, x ≠ - 1 for reason given above, then
solution is x = 
I think it's A. Sorry if I get it wrong.