Initial table of data before analyzing the time quantities; w is tailwind speed.
SPEED TIME DISTANCE
WITHWIND 155+w 650
AGAINSTWD 155-w 650
SPEED TIME DISTANCE
WITHWIND 155+w 650/(155+w) 650
AGAINSTWD 155-w 650/(155-w) 650
Concentrate on the part of the description, Flying against a headwind, it takes
2 hours longer to complete the return trip.
This means .
The rest is arithmetic to solve the equation for w, the speed of the wind.