Let's denote the interest rates for account A and B as A% and B% respectively.
From the information given, we can set up a system of two equations:
* 3000A% + 6000B% = 270 (Jimmy's interest)
* 5000A% + 3000B% = 275 (Jenny's interest)
Solving this system of equations will give us the interest rates for accounts A and B.