Rashi in Menachot 49(b)indicates that 22 lambs were needed. This is enough for the temidim on each day, one day Rosh Hashanah, and one day rosh chodesh. I remember reading in reference to the Jewish calendar that they did not accept witnesses in the afternoon so as to avoid the problem of not having time to bring the musafim. It thus appears that only one day Rosh Hashanah was celebrated in the Beit Hamikdash with musafim. Why does does the text refer to two days Rosh Hashanah if musafim were only broght on one day?
Michael S. Winokur, Forest Hills, New York
The two days of Rosh Hashanah were relevant only with regard to the Korban Tamid.
One day of Rosh Hashanah needs 14 Musafim, seven for the Musaf of Rosh Hashanah and seven for the Musaf of Rosh Chodesh. Include the two for Shabbos and the total is sixteen. (See Shitah Mekubetzes in the margin, who asks your question and the note there which answers the above.)