Original sentence: In 430 BCE, he determined the length of the tropical year to be about 365 days, 6 hrs and 19 mins, which is 31 minutes longer than the modern value.It gives exactly 6940 days to one 19-year cycle
Edited sentence: In 430 BCE, he determined the length of the tropical year to be 365 days, 6 hrs and 19 mins, which is just 31 minutes longer than the modern value, and thus 99.43 per cent accurate