Percent composition of Silver (two naturally occurring isotopes)

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Homework Statement

Silver has two naturally occurring isotopes: Ag−107 with a mass of 106.905 amu and a natural abundance of 51.84 %, and Ag−109. Use the atomic mass of silver listed in the periodic table to determine the mass of Ag−109.
express answer to 4 sig-figs and use appropriate units

Homework Equations

ATomic mass of silver is listed in PT as 107.868

The Attempt at a Solution

x = [107.868 - (106.905 * 0.5184)] / 0.4184

x = 125.4amu

= wrong

not sure what I am doing wrong, thanks for any help

 

[SammyS]

Homework Statement

Silver has two naturally occurring isotopes: Ag−107 with a mass of 106.905 amu and a natural abundance of 51.84 %, and Ag−109. Use the atomic mass of silver listed in the periodic table to determine the mass of Ag−109.
express answer to 4 sig-figs and use appropriate units

Homework Equations

ATomic mass of silver is listed in PT as 107.868

The Attempt at a Solution

x = [107.868 - (106.905 * 0.5184)] / 0.4184

x = 125.4amu
= wrong

not sure what I am doing wrong, thanks for any help

If there are only two naturally occurring isotopes, and one of them, Ag-107 has natural abundance of 51.84 %, then what is the natural abundance of the other naturally occurring isotope, Ag-109 ?