Irene's grandfather arrived in Sydney from Athens at 10 pm on Friday after a 25-hour trip. The flight began at 12 noon on Thursday, Athens time. What is the time difference between Athens and Sydney?

The question is incomplete:

Irene's grandfather arrived in Sydney from Athens at 10 pm on Friday after a 25-hour trip. The flight began at 12 noon on Thursday, Athens time. What is the time difference between Athens and Sydney?

A. Athens time is 9 hours behind  Sydney time.

B. Athens time is 9 hours ahead of  Sydney time.

C. Athens time is 15 hours behind  Sydney time.

D. Athens time is 15 hours ahead of  Sydney time.

A. Athens time is 9 hours behind  Sydney time.

Step-by-step explanation:

The statement indicates that the flight began at 12 noon on Thursday, Athens time and that it lasted 25 hours. So, you can calculate the Athens time when he arrived after 25 hours which would be 1 pm on Friday. Also, the statement says that Irene's grandfather arrived in Sydney at 10 pm on Friday and now we know that at that moment it was 1 pm on Friday, Athens time. From these, you can calculate the difference between 1 pm and 10 pm that would be 9 hours. Because of this, the answer is that the time difference between Athens and Sydney is that Athens time is 9 hours behind  Sydney time.