The cycle of the moon's phases runs 29.53 days.
7 days
The full lunar cycle is roughly 4 weeks, and from full-moon to new-moon is half the cycle, so it would take (roughly) 2 weeks to go from full to new moon.
On average, 29 1/2 days.
29.53 days is a synodic period. One Full Moon to the next.
A full cycle is about 29.5 days, so a quarter cycle will be 1/4 of this, on average (divide 29.5 by 4). This is just an average; since the Moon's orbit is not a perfect circle, it may vary a bit.
1 month.
29.53 days
29.53 days
28 days
29.5 days
29 and 1/2 days.
7 days
7 days
29.5 days
29.5 days
28 days
29.5 days from new moon to new moon.