Flying against the wind, a jet travels 6930 miles in 9 hours. Flying with the wind, the same jet travels 6060 miles in 6 hours. What is the rate of the jet in still air and what is the rate of the wind?
Let a be the speed the jet travels, and let b be the speed the wind travels.
$9(a-b)=6930$
$a-b=\frac{6930}9=770$
$6(a+b)=6060$
$a+b=\frac{6060}6=1010$
$a+b=770$
$a-b=1010$
You can finish the rest :)