Yeah I think I just diagramed my answer out for me. If A (earth) pulls B and C, and B and C also pull on A, then the net force on B would be A + the pull of B, and since B is also (proportionate to) the mass of B, then it cancels out. Same goes for C. therefore you're left with the same acceleration for B and C.

Sorry if I didn't word that clearly but yeah I think I see what I was missing.

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I'm like one of those idiot savants...well, except for the savant part.