Magnesium has three isotopes, 24Mg, 25Mg and 26Mg . The relative abundance of the 26Mg isotope is 10%.The relative atomic mass of Mg is 24.3 . What is the relative abundance of the 24Mg isotope ?

Answer 1

relative abundance 26 = 10% or 0.1
relative abundance 24 = x
relative abundance 25 = 90-x or 0.9-x
Then 24x + 26(0.1) + 25(0.9-x) = 24.3
Solve for x