Explanation:
The graph says when the moon's visibility is 0%, then that's when a new moon has happened.
So in terms of the graph, whenever your y value is at 0, then that's when there's a new moon.
So for the questions:
The first new moon of the year was on day 24.
The second new moon of the year was on day 51.
For the last question, just take the difference of the two numbers.
51 - 24 = 27
Therefore, the period between the two new moons is approximately 27 days long.