Question

How much time does the moon take to revolve around the earth
earth.
27 or 29 days?

Answer 1

The sidereal month is the time it takes to make one complete orbit around Earth with respect to the fixed stars. It is about 27.32 days. The synodic month is the time it takes the Moon to reach the same visual phase. This varies notably throughout the year, but averages around 29.53 days.

No need to concentrate on the specifics, but you can say that the moon takes 27 days sometimes and other times it takes 29 days.