Flying with the wind, a plane can travel 840 miles in 4 hours. Against the wind, the plane requires 5 hours to fly the same distance. Find the speed of the plane in calm air and the speed of the wind, both in miles per hour.

Kilgore trout creates a new scale to diagnose depression. however, his scale only assesses one symptom of depression while ignoring others. which of the following is his new scale most likely lacking? a) test-retest reliability b) discriminant validity c) criterion validity d) alternate-forms reliability e) content validity f) none of the above