I am currently a Chemistry major at Georgia Tech and am considering staying an extra semester to complete a double major in Public Policy.I have about a 3.0 GPA in terms of Chemistry classes and a 3.7 in terms of Public Policy classes
On the School Report that LSAC sends to each of the schools you apply to, LSAC computes your overall GPA and that's what schools will see. However, if your goal is to highlight each major's GPA, you can do so on your résumé by pointing out the GPA you got in each of your majors, in addition to your overall GPA.
It could look something like this:
Overall GPA: 3.2
GPA in Chemistry major: 3.0 (department-wide average in Chemistry is 2.72)
GPA in Public Policy major: 3.7 (department-wide average in Public Policy is 3.45)
This can be particularly useful if your majors are higher that the department-wide average or if your overall GPA is on the low end, but your individual major GPAs are both higher than the overall and look good when compared to department-wide averages.