At 10:00, John and Leslie left home and walked in the same direction. John walked at 4km/h and Leslie walked at 3km/h. At 10:15, their dog, Dexter, running at 6km/h left home to run after them. The dog ran until he caught up with John, then immediately turned around and ran back to Leslie. At what time did Leslie meet Dexter on Dexter's way back?

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