A:
All praise be to Allah Alone, and peace and blessings be upon His Messenger, and his family and Companions.
It is sufficient
for them to perform Tayammum once for offering more than one obligatory Salah or supererogatory ones as long as they remain in a state of Taharah (ritual purification) [have not invalidated Tayammum] and cannot find water. This is according to the more correct of the two opinions held by the scholars.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.