Context: The Gregorian calendar improves the approximation made by the Julian calendar by skipping three Julian leap days in every 400 years, giving an average year of 365.2425 mean solar days long. This approximation has an error of about one day per 3,300 years with respect to the mean tropical year. However, because of the precession of the equinoxes, the error with respect to the vernal equinox (which occurs, on average, 365.24237 days apart near 2000) is 1 day every 7,700 years, assuming a constant time interval between vernal equinoxes, which is not true. By any criterion, the Gregorian calendar is substantially more accurate than the 1 day in 128 years error of the Julian calendar (average year 365.25 days).

Question: The Gregorian calendar is an improvement over what other calendar?
Answer: Julian

Question: How many days must be skipped to align the calendar with mean solar days in a year?
Answer: three Julian leap days

Question: What is the approximate error for every 3,300 years?
Answer: one day

Question: What is the error rate of the vernal equinox per every 7,700 years?
Answer: 1 day

Question: What was the error rate in the Julian calendar?
Answer: 1 day in 128 years

Question: How does Julian calendar improve the approximations made by the Gregorian calendar?
Answer: Unanswerable

Question: How many years does it take for the Julian approximation to have an error of one day?
Answer: Unanswerable

Question: In the Julia system what is the error rate for the vernal equinox first 7700 years?
Answer: Unanswerable

Question: The Julian system skips three leap days and how many years?
Answer: Unanswerable