On adding excess of AgNO₃  solution into 0.01 mole complex compound PtBr₄. xNH₃, 0.03 moles yellow precipitate was obtained, then value of 'x' is : 

PtBr₄. xNH₃ + AgNO₃ solution $\to$ AgBr (ppt) 

0.01 mole         Excess                  0.03 moles

:. The value of x = 5 

i.e., complex is [Pt Br(NH₃)₆]Br₃