Part (a) is fine, but I can't do part (b). I've formed the MRS for each pair of bundle (so 3 in total) and equalised them to their corresponding pi/pj. Then there's the constraint of p1x1 + p2x2 + p3x3 = w1p1 + w2p2 + w3p3. So if I take consumer A (i.e. individual who holds 10 of good 1), then the constaint would be p1x1 + p2x2 + p3x3 = 10p1. If that's the case and I form the marshallian demand for good 1 (and do the same for the other bundle involving good 1) I can set the sum of the two to the total amount of good 1, that is 1000, satisfying the market clearing condition. However, if I form the other market clearing condition for the other two good as well, it's very tedious to set one price as numeraire and solve for relative prices.
Am I doing this right?
... and the ones that won't