Answer
Air speed: 2.25 mi/h
Wind speed: 0.75 mi/h
Work Step by Step
Let "a" be air speed and "w" be wind speed
We have: a+w=3 (tailwind)
a-w=1.5 (headwind)
Elimination method: (a+w)-(a-w)=3-1.5 => a-a+w+w=1.5 => 2w=1.5 => w=0.75
a+0.75=3 => a=3-0.75=> a=2.25
Air speed: 2.25 mi/h
Wind speed: 0.75 mi/h