Identify the logic gates marked P and Q in the given logic circuit. Write down the Boolean expression for this logic circuit and truth table.

Explanation

Here gate P is OR gate and gate Q is NAND gate. The Boolean expression for this logic circuit is
`y=bar((A+B).B)=bar(A+B)+barB`
Truth table of this logic circuit is given below
`|{:(A,B,(A+B),(A+B.)B,y=bar((A+B).B)),(0,0,0,0,1),(0,1,1,1,0),(1,0,1,0,1),(1,1,1,1,0):}:|`