1. The problem statement, all variables and given/known data (a) The diagram represents a NAND gate with two inputs, T1 and T2, and an output X. Copy the truth table above and complete it. Show how a NAND gate can become a NOT gate. (b) Draw up a truth table for the combination of NAND gates shown above. 2. The attempt at a solution (a) The truth table: A NAND gate is an AND and a NOT gate: (b) First of all, I shall add letters to the graph: I got two truth tables and not sure which one is correct. Are they both correct in this situation (so the problem has two solutions)? Looks like the answer depends on what combination does one put in the first two columns: 00 10 01 11 or 00 01 10 11 (specifically 10 01 or 01 10).