Verified answer

Turtles in the wild sometimes go for that long without food. You could feed it well before you leave and right after you come back. Alternatively, put some bait fish in the tank and let the turtle feed itself.

Leave the turtle in water, with access to land for basking. The aquarium heater should maintain the temperature and the basking lights should be on a timer. If the turtle does get cold, it will just slow down its metabolic rate, decreasing its need for food a little.

Baby turtles need to be offered food daily while SOME ADULTS may only need food two to three times a week. I feel more comfortable offering them something each day. I also heard that sick turtles can go without food for weeks, even months, and when it feels well again, it'll eat again. I'm not sure if that can also apply to healthy turtles. Try seeking professional advise from a vet. Remeber I said some adults not all. I'm not a professional.