Answer:
$4
Step-by-step explanation:
Total consumer surplus is given by the difference between the willingness to pay of each customer to the actual price of a good.
Since Avery is only willing to pay $10 and the pizza costs $12, Avery will not buy a pizza and should not be considered for consumer surplus.
Since Pia is willing to pay $13, and Sylvio is willing to pay $15, consumer surplus is:

When the price of pizza is $12, a consumer surplus of $4 is achieved.
 
        
             
        
        
        
A question: 
(5.3 x 10 to the 6th power) + 8.2  10 to the 6th power)
A solution:
Multiply 10 x 10 6 times to get rid of the two powers.
(5.3 x 1,000,000) + (8.2 x 1,000,000)
Multiply inside the parenthises.
 (5,300,000) + (8,200,000)
Add:
13,500,000.
A answer: 
13, 500,000.
B question:
(6.5 x 10 to the 7th power) / (5 x 10 to the 3rd power)
B solution:
Again, get rid of the powers.
(6.5 x 10,000,000) / (5 x 1,000)
Multiply inside the parenthesis:
(65,000,000) / (5,000)
Divide:
13,000
B answer:
13,000.
C question:
(4.6 x 10 to the 6th power) (3 x 10 to the 5th power) / (2 x 10 to the 7th power)
C solution:
Get rid of powers:
(4.6 x 1,000,000) (3 x 100,000) / (2 x 10,000,000)
Multiply: 
(4,600,000) (300,000) / (20,000,000)
multiply in the left side:
(1,380,000,000,000) / (20,000,000)
divide:
69,000
C answer:
69,000
        
             
        
        
        
Answer:
1/32768 
Step-by-step explanation:
We have 5 digit pin code plots and 8 choices per slot. Because repetition is allowed (1 digit can have 8 choices) so we multiply out the number of choices per slot
. Hence: 
8*8*8*8*8 =  
 
So there are 32768 different combination. 
But correct guess on the first try is just only 1 time, so its' probability: 
1/32768