'According to the following diagram, approximately how much time goes by between phase H and phase B? Explain your answer.'
I'll try to explain this as simply as possible. A single moon cycle is 29 and a half days. Each individual cycle takes approximately 3 and a half days to transition to the next phase, so if you want to know how much time goes by between phase H and phase B, you would multiply 3.5 by however many phases there are between H and B. The answer is approximately 11 or so days.
I hope this helped!