Answer :
Lets get this organized:-
Atomic number ⇔ Protons
54 ⇔ 54 protons
Atomic mass ⇒ Protons + Neutrons
? ⇒ 54 + 77
54 + 77 = 131
The atomic mass would equal →→→ 131
So, our final answer would be 131
Atomic number ⇔ Protons
54 ⇔ 54 protons
Atomic mass ⇒ Protons + Neutrons
? ⇒ 54 + 77
54 + 77 = 131
The atomic mass would equal →→→ 131
So, our final answer would be 131