In Beauty and the Beast (2017 film), a petal is seen falling pretty often, but there are only so many petals on a rose and considering it's been about 10 years. I'm confused as to how often a petal falls please help.
It's never mentioned in the movie, and no time frame (other than it having been about 10 years) is given; so no one can say for sure. Furthermore, it's an enchanted rose that lives considerably longer than a normal rose would, so it could have been created to decay at a very specific rate (set by the enchantress).
That being said, assuming the rose mimics the decaying of a normal rose (but at an increased timescale, it stands to reason that the rate at which the petals fall increases exponentially. As the rose is closer to dying, the last few petals will fall off considerably faster than the first few petals did.
Also, keep in mind that we don't have an exact timeframe for the events in the movie, so we can't even be sure about how much time has passed between the falling petals in the movie. But you are correct that the petals could not have been falling at a constant rate, since no rose would have enough petals to account for 10 years.