Answer: 
Step-by-step explanation:
The complete exercise is: "The circumference of a circle is 47.1 and the diameter of the circle is 15. Which best represents the value of π? "
In order to solve this exercise, it is important to remember that the circle can be calculated with the following formulas:
1. 
Where "C" is the circumference of the circle and "D" is the diameter of the circle.
2. 
Where "C" is the circumference of the circle and "r" is the radius of the circle (Remeber that the diameter is twice the radius).
In this case, the exercise gives you the circumference of the circle and its diameter. These are:

Then, knowing those values, you can substitute them s into the first equation
, as following:

The final step is to solve for
:

<h3><u>Answer</u>:- </h3>

<h3><u>Solution:-</u></h3>
<u>Given </u><u>that </u><u>:</u><u>-</u>
- job last for h hours
- Cost of job lasting more than 1 hour = $30
- Cost for the first hour = $75
Remaining hours for which the job will last after first hour= (h-1)
<u>Therefore</u>,
Cost for subsequent hours = 30×(h-1)
= 30(h-1)
Total Cost for job = Cost for 1st hour + Cost for subsequent hours

Answer:

Step-by-step explanation:
add 4 on both sides
leaves you with 15 on the right side
you then divide by negative 2
since you divide by a negative you have to switch the sign