This Chem problem is really difficult -Need help please!

Magnesium Consists of three naturally occuring isotopes. The percent abundance of these isotopes is as follows: 24Mg(78.70%), 25Mg(10.13%) and 26Mg(11.7%). The average atomic mass of the three isotopes is 24.3050amu. If the atomic mass of 25Mg is 24.98584 amu and 26Mg is 25.98259amu, calculate the actual atomic mass of 24Mg.

3 answers

0.7870*y + (0.1013*(24.98584) + (0.117*(25.98259) = 24.3050
Solve for y

23.804

23.805 amu