Answer:
11.4
20/100 = x/57
Step-by-step explanation:
It is perhaps simplest just to translate the given English sentence into a mathematical sentence.
... 20% ... ... of ... 57 ... is ... what number
... 20/100 ... × ... 57 .... = ... what number . . . . . . . . translation to math sentence
... 11.4 = what number . . . . . . . . carry out the multiplication
_____
If you're asked to write this as a proportion, you can write it like this:

You can solve this proportion by multiplying by 57 (the denominator under "what number"). Doing so gives you the same arithmetic sentence as shown above.
Hi, do you have to picture?
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
Answer: 12+4+4
Step-by-step explanation:
Because if you add those together you get 20 miles per hour
Answer: x = (cd + by) / a
Working out:
(ax - by) / c = d
1)Multiply by c on both sides to get:
ax - by = cd
2) Add by on both sides to get:
ax = cd + by
3) divide by a on both sides to get:
x = (cd + by) / a