Determine travel for different rate springs in series

I've found a lot of information about calculating combined spring RATE, but none of the examples talk about the force experienced by each individual spring when multiple springs are "stacked" in series.

For instance, I have two springs on top of each other:

8 \
8 |
8 |_____ This spring has a rate of 300lbs per inch (Spring A)
8 |
8 /
-
8 \_____ This spring has a rate of 250lbs per inch (Spring B)
8 /


The rate of the system will be SpA * SpB / (SpA + SpB) = ~136.4lbs per inch.

How do I determine the amount of compression each individual spring experiences for a given amount of force? For instance, with 300 lbs applied to the system, how much does Spring A compress, and how much does Spring B compress?