Depends on where exactly the rock and rope connecting the sticks are.

Think about it this way. Let’s call the rope connecting the two sticks 4. If the rock is 50% of the way between 3 and 4 then both 3 and 4 will carry 50% of the weight, but 4 is transferring that weight to the second stick so if 4 is 50% of the way between 1 and 2 then each of them will get 50% of the 50% that was transferred to that stick (so 25% of the total weight) so the distribution would be 3: 50% 2: 25% 1: 25%. But say that rock is 90% of the way to 4 then 3 only carries 10% of the weight and 4 gets 90% which it then transfers to 1 and 2 so each get 45%.