The distance from Jupiter to Neptune is 24.89 AU and it would take light 3.45 hours to cover that distance.
Either your question is wrong or it is asking something different.
AU or Astronomical Unit, is a measurement of distance, not time. It is the measurement of the average distance from to . Now, if you’re asking how FAR is it from Jupiter to Neptune in AU, then we can get an answer.
The distance is 2,313,267,138 miles, 3,722,670,000 kilometers or 24.89 AU.
For a measurement of time, a speed must be speculated. If we assume the speed of light ( 186282m/s, 299792.5 km/s or 7.21436 AU/h) it would take 3.45 hours.