Karachi is 2 hours ahead of Cairo
Best overlap: 8:00 AM to 4:00 PM in Cairo is 10:00 AM to 6:00 PM in Karachi.
Shoot for 8:00 AM to 4:00 PM in Cairo; your Karachi colleagues will see that as 10:00 AM to 6:00 PM. The overlap is wide at 8 hours, so you can protect mornings for deep work and still find plenty of meeting time. Note that Cairo follows daylight saving while Karachi stays put, so the times above drift by an hour seasonally.