SOLUTION: the average rate of an airplane in still air is 220 mph. Traveling with the jet stream the airplane can fly 1600 in the same time it takes the airplane to fly 600 miles into the je

Let x be the rate of the jet stream.


Then the effective speed ("the ground speed") of the airplane flying with  the jet is

220 + x miles per hour.     (1)   



The effective speed ("the ground speed") of the airplane flying against  the jet is

220 - x miles per hour.     (2)   



The time equation is


     = .



To solve it, cross-multiply


    1600*(220-x) = 600*(220+x)


and simplify step by step


    8*(220-x)    = 3*(220+x)

    8*220 - 8x   = 3*200 + 3x

    8*220 - 3*220 = 3x + 8x

    5*220         = 11x'

    x             =  = 5*20 = 100.


ANSWER.  The rate of the jet stream is  100 miles per hour.

    1.  The effective speed of a plane flying with    a wind (with a jet) is the sum        of the two speeds.

    2.  The effective speed of a plane flying against a wind (against a jet) is the difference of the two speeds.

    3.  Write and use the time equation to solve the problem.