Alright, so this is simple.
P= 50,000 or 50 thousands
G= 13 Tons
The variable f isn't known.
So your equation would be 13 = 50 (f), if you were to put your known variables in the equation.
If you were to find variable f, you would divide 13 tons by 50,000 to get 0.00026 or in scientific notation: 2.6 x 10 (exponent(s):-4)
Answer: 
<u>Step-by-step explanation:</u>
(4, 1) & (2, -5)
First, find the slope (m) and then the perpendicular (opposite reciprocal) slope:

Next, find the midpoint of (4, 1) and (2, -5):

Lastly, input the perpendicular slope and the midpoint into the Point-Slope formula to find the equation of the line:

A= 1
B= -5
C= 10
In order to figure it out, you can think about it like this..
The answer to this is 10 39/88.
100×16.60=1,660
Sam cost
1,660+1,660×0.06=1,759.6