Bismillah Walhamdulillah Was Salaatu Was Salaam 'ala Rasulillah

 Narrated Anas (Radi-Allahu 'anhu):

Abu Bakr wrote to me what Allah's Apostle (Sallallahu 'Alaihi Wa Sallam)
has made compulsory (regarding Zakat) and this was mentioned in it: If a
property is equally owned by two partners, they should pay the combined
Zakat and it will be considered that both of them have paid their Zakat
equally.

Bukhari Vol. 2 : No. 531