The way you find profit is to subtract the revenue and the cost
Profit = Revenue - Cost
The revenue is the amount of money coming in, the cost is the amount of money going out. The goal of course is to have the revenue larger than the cost so that the profit is positive. 
So the equation given is
P = 7.5n - (2.25n+15)
and its in the form
P = R - C
where...
R = 7.5n is the revenue equation
C = 2.25n+15 is the cost equation
Focus on the revenue equation
R = 7.5n
which is the same as 
R = 7.50*n
This tells us that Sandra pulls in a total of 7.50*n dollars where n is some positive whole number. It represents the number of necklaces sold. For example, if she sold n = 10 necklaces, then
R = 7.50*n
R = 7.50*10
R = 750
meaning that Sandra has made $750 in revenue
As you can see above, the revenue is computed by multiplying the price per necklace ($7.50) by the number of necklaces sold (n) to get R = 7.50*n
So that's why the answer is $7.50
Note: The 2.25 is part of the cost equation. This is known as the variable cost. It is the cost to make one necklace ignoring the fixed cost (eg: rent). The variable cost often doesn't stay the same, but algebra textbooks often simplify this aspect. 
        
             
        
        
        
Step-by-step explanation:
I am sorry but please give detailed question 
 
        
             
        
        
        
Answer
60 hours = 2.5 days
Step-by-step explanation:
1 day = 24 hours
2 days = 48 hours
3 days = 72 hours
so 60 hours in = to 2.5 days
hope this helps
 
        
                    
             
        
        
        
Answer:
+49
Step-by-step explanation:
-7 x -7 = +49 because the negatives cancel out, resulting in a positive
 
        
                    
             
        
        
        
Answer:
i think the answer would be 95 degree. im not absolutley positive though
Step-by-step explanation:
i added 35 and 50 and got the sum of 85 then i subtracted 85 from 180 and got 95
feedback is appreciated.
(i'm not gonna beg for brainliest)