Speed is inversely proportional to Time taken for a given distance.
Speed ratio of Ong : Lee = >6:4
The distance covered at a given time when they meet is also proportional to speed.
At the point where they meet, Ong Traveled : Lee Traveled => 6:4
That means when they met, Ong traveled 60% of the journey from Y to X
and Lee traveled 40% of the journey from X to Y
From Ong’s perspective, 60% of the journey is also 60% of her total time.
60% of 4hr => 2.4 hr or 2 hr 24 min
Time from 9am will be 11:24 am. ###
You can also work from Lee’s perspective, i.e he had traveled 40% of the journey when they met.
40% of his 6hr total time is also 2.4 hrs.