Kat lives in New York and she visits her cousin Jenny, who lives in Sydney.

Kat leaves New York on Friday at 1400, local time on a 6.5-hour flight to San Francisco.

New York is 3 hours ahead of San Francisco.

She spends 24 hours in San Francisco.

She then catches a 15-hour flight to Sydney.

The time in Sydney is 18 hours ahead of San Francisco.