How to find the abundance of Boron's 2 isotopes??

Question

10.81=x(10.01294) + x(11.00931)

In this question I have to find the relative abundance of Boron's two isotopes 10 and 11, so how to find the X?

10.81 is the average atomic mass of Boron.

Thank you!!

Answer 1

I'm not sure if this is right, but I'm 90% it is. =p

{x(10) + [11(100-x)]}/100 = 10.81

10x+1100-11x = 1081

10x-11x = 1081-1100

-1x = -19

1x = 19

x = 19% for B10 and

100% - 19% = 81% for B11

Hope this helps!!