certification E20 324

Hi all

I am struggling with some of the questions in the practice E20-324 tests, I have been uisng the video based course. Can anyone help and explain how to calculate the answer of this example please?

below the question;

SnapView snapshot to be made of a clone prior to resynchronization. The source LUN is 256 GiB, and performs 500 random reads/s and 25 random writes/s of 8 KiB. The clone will be fractured every 15 minutes, and resynchronized after the snapshot is started. How many COFWs will be performed each time the clone is resynchronized?

A. 45,000

B. 22,500

1. C. 112,500
2. D. 56,250