MCQ - 516-13283

Correct Answer: D

Explanation:

$\genfrac{}{}{1px}{}{1800}{3}$ = u + v ------- (1) is the equation for the flight with the wind.

(Here "u" is the airspeed of the airplane with NO wind, "v" is the wind speed)

$\genfrac{}{}{1px}{}{1800}{3}$ = u - v ------- (2) is the equation for the flight against the wind.

Simplify equations (1) and (2) and write them as a system:

u + v = 600 ------ (1')

u - v = 450. ------ (2')

Now add the two equations (1') and (2'). You will get

2u = 1050 ---> u = $\genfrac{}{}{1px}{}{1050}{2}$ = 525 miles per hour

Having this, you can easily determine "v" from (1'):

v = 600 - 525 = 75 miles per hour

The plane airspeed is 525 mph. The wind speed is 75 mph.