Look this over and let me know if it looks ok.
We are given our original equation: the cost C (in dollars) per passenger is:
C(x) = 100 + x/10 + 36,000/x Where x is the ground speed (airspeed + - wind).
We are also given: A Boeing 747 crosses the Atlantic Ocean (3000 miles) with an air speed of 500 miles per hour.
Now we are asked to find the cost per passenger for quiescent (no wind) conditions?
Using the above equation all we have to do is replace the speed of the plane (500 mpr) in place of x. The equation is as follows:
100 + 500/10 + 36,000/500 = $222
We can see that the cost per passenger for quiescent (no wind) conditions is $222
Does this look correct?