It's kind of not C.
Solve this proportion for 'x':
3/50 = x/2400
Hint: Cross-multiply the proportion, then do what you need to do.
Given:
The function that represents how the amount of fuel changes as a function of distance flown is

where x represents miles flown, and f(x) represents the amount of fuel remaining.
To find:
The rate of change for this scenario.
Solution:
The slope intercept form of a linear function is
...(i)
Where, m is the slope or rate of change and b is the y-intercept.
We have,
...(ii)
On comparing (i) and (ii), we get

Therefore, the rate of change for this scenario is -0.9. It means, the amount of fuel in the airplane is decreasing by 0.9 gallons per mile.
Answer:
Step-by-step explanation:
Find c if ∠PQR = 90°?
I will ASSUME you mean point P is at (3. c)
slope of PQ is (2 - c) / (9 - 3) = (2 - c) / 6
slope of QR is (11 - 2) / (3c - 9) = 9 / (3c - 9)
perpendicular lines have negative reciprocal slopes.
(2 - c) / 6 = -1(3c - 9)/9
9(2 - c) = -6(3c - 9)
18 - 9c = -18c + 54
9c = 36
c = 4