Flight Soekarno–Hatta International Airport departs from Jakarta Soekarno–Hatta International Airport at 09:35 and arrives at Singapore Changi Airport at 12:30.
The flighttime is about 1h 55m. The distance travelled ("as the bird flies"): 369 Km. So the average speed is roughly 193 Km.
There is an 1 hour time difference between Jakarta and Singapore