First Jet:
Distance=X
Rate=564km/h
Time=X÷564
Jet 2:
Distance=X
Rate=744
Time=X÷744
For the first one and a half hour, the jet has travelled 564*1.5=846km
difference in speed= 744-564=180
for every 1 hour it travels 180km more than jet 1
846÷180=4.8hours
ps I don't know if this is the kind of equation you are looking for
