Question

One jet flies at a ground speed of 75 miles per hour faster than another jet. on a particular flight the faster jet requires 3 hours and the slower one 3 hours and 36 minutes. what is the length of the flight

Answer 1

It is a distance-speed-time problem. Applying the general formula of $s=vt$, we'll solve this problem. If the speed of the second jet is $v$, then the speed of the first jet is $75+v$ according to the problem. The first jet requires 3 hours and 36 minutes (3.6 hours) and the second one 3 hours. 
By setting up an equation we can write that $3(v+75) = 3.6v$ and $v=375$
The length of flight is $s=vt=375*3.6=$ or $450*3=1350$ miles