what's the relative atomic mass of an unknown metal if?

Question

Isotope 1;
relative isotopic mass- 63.0
% abundance- 77.2

Isotope 2;
rel. isotopic mass- 65.0
% abundance- 22.8

when i calculate the relative atomic mass of the element i got 4878.42 i think it's wrong..


anyone help me pls..

Answer 1

Try
M = (63*0.778+65*0.228)