Answer:
- jet in still air: 712 mi/h
- jetstream rate: 50 mi/h
Step-by-step explanation:
The relation between speed, time, and distance is ...
speed = distance/time
Against the wind, the speed is ...
(3310 mi)/(5 h) = 662 mi/h
With the wind, the speed is ...
(3810 mi)/(5 h) = 762 mi/h
The jet stream adds to the speed in one direction, and subtracts in the other direction, so the difference in travel speeds is twice the speed of the jet stream:
(762 mi/h -662 mi/h)/2 = jet stream speed = 50 mi/h
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The speed of the plane is the average of the two speeds, or the sum of jet stream speed and the lower speed, or the difference of the higher speed and the jet stream speed. Any of these calculations will give the plane's speed in still air:
(762+662)/2 = 662 +50 = 762 -50 = 712 . . . mi/h
