So with the attempts at this puzzle so far it looks as if it is actually less open than I thought. The fact that all of the sum totals must add up to a constant (412) means that only a few sets of totals work. If you aim for all four of Σa, Σb, Σc, and Σd being equal, they come out as 103 each. So I'm updating this puzzle with the end points I'd like to aim for:
102, 102, 103, 105
If this doesn't work we'll try the simpler:
102, 102, 102, 106
It's arbitrary which variable takes which value, but remember whichever has the highest value can't be present on the zero car (point 5 of the original challenge)
102, 102, 103, 105
If this doesn't work we'll try the simpler:
102, 102, 102, 106
It's arbitrary which variable takes which value, but remember whichever has the highest value can't be present on the zero car (point 5 of the original challenge)



