Total interest=7.25% of 2560=185.60.
If she invested x in the 6% one then she invested (2560-x) in the other.
So 185.60=0.06x+0.08(2560-x)=0.06x+204.80-0.08x.
Therefore 0.02x=204.80-185.60=19.20.
x=19.20/0.02=1920/2=960 and 2560-x=1600.
She invested 960 @ 6% and 1600 @ 8%.