Your answer, "Six", is not correct.
The correct answer to
How many days after Jesus take Peter, James and John to a high mountain?
is
Eight
as shown by
Luke 9:28
which is
- KJV
- And it came to pass about an eight days after these sayings, he took Peter and John and James, and went up into a mountain to pray.
- NIV
- About eight days after Jesus said this, he took Peter, John and James with him and went up onto a mountain to pray.