Forces exerted on 3 blocks, almost done please help!

Three blocks of masses 2kg, 3kg, 5kg are lined up on a frictionless table respectively. All three are pushed to the right by a force of 12N.
a) how much force does the 5kg block exert on the 3kg block?

b) how much force does the 2kg block exert on the 3kg block?

as a system the acceleration = 1.2m/s^2 and the net force for the 2kg, 3kg, 5kg blocks are 2.4N, 3.6N, and 6N respectively. (all my own calculations) I just cant figure out how to determine the forces in between the blocks!!!

Please help, Im not looking to cheat, Im looking to understand.

The only thing in contact with the 5kg block, that can produce horizontal motion, is the 3kg block. So the net force ,you found, on the 5kg block is due to the force the 3kg block exerts on it. Then from 3rd law the 5kg block exerts an equal & opposite force back on the 3kg block.

b) The net force Fn on the 3kg block is due to the 2kg block pushing right F12 and due to the 5kg block pushing left F32 as;
Fn = F12 - F32
F12 = Fn + F32

where you found Fn=3.6N and we found above F32=6N
So
F12 = 9.6N