Explanation

Zoology has 7 letters in total, with O repeated thrice 7!/3! → 7∗6∗5∗4∗3∗2∗1/3∗2∗1 = 840ways

Zoology has 7 letters in total, with O repeated thrice 7!/3! → 7∗6∗5∗4∗3∗2∗1/3∗2∗1 = 840ways