Before being put out of service, the supersonic jet Concorde made a trip averaging 120 mi/h less than the speed of sound for 0.1 h and 410 mi/h more than the speed of sound for 3.0 h. If the trip covered 3,990 mi, what is the speed of sound?

894.19 mi/hr

Step-by-step explanation:

Total distance of the trip = 3990 mi

Let the speed of the sound be 'x' miles per hour

Now,

Total distance = Speed * Time

Therefore,

According to the question

3,990 mi = [ (x - 120) * 0.1 ] + [ (x + 410) * 3.0 ]

or

3,990 mi = 0.1x - 12 + 3x + 1230

or

0.1x + 3x = 2772

or

3.1x = 2772

or

x = 894.19 mi/hr