I want to know if 2 or 3 Salah can be performed with one Wudhu or Ghusl.
The simple answer is yes, as long as you don't break wudu' you can pray as many prayers as you like. But it is much better and recommended to perform wudu' for each prayer as the well known hadith about Bilal's footsteps in paradise suggests. A clearer evidence is:
The Messenger of Allah (ﷺ) performed five prayers with the same ablution of the occasion of the capture of Mecca, and he wiped over his socks. ‘Umar said to him(the Prophet): I saw you doing a thing today that you never did. He said: I did it deliberately. (Sunan Abi Dawod)
This link presents a list of people who prayed the fajr prayer with the wudu' of Isha' prayer.