Answer: the speed of the commercial jet is 540 mph
the speed of the private airplane is 330 mph
Step-by-step explanation:
Let x represent the speed of the commercial jet and
Let y represent the speed of the private airplane.
It takes the commercial jet 1.1 hours for the flight from Denver to Phoenix.
Distance = speed × time
Therefore, distance covered by the commercial jet from Denver to Phoenix would be
1.1 × x = 1.1x
it takes the private airplane 1.8 hours to cover the same distance. The speed of the commercial jet is 210 miles per hour faster than the speed of the private airplane. It means that
y = x - 210
Distance covered by the private airplane would be
1.8(x - 210) = 1.8x - 378
Since the distance is the same, then
1.8x - 378 = 1.1x
1.8x - 1.1x = 378
0.7x = 378
x = 378/0.7 = 540
y = x - 210 = 540 - 210
y = 330
