### 5. What is the minimum number of two-input NAND gates used to perform the function of two input OR gate ?

### 46. Which one of the following logic expression is incorrect?

### 48. The black box in the following figure consists of a minimum complexity circuit that uses only AND,OR and NOT gates. The function f (x,y,z) = 1 whenever x , y are different and 0 otherwise. In addition the 3 inputs x,y,z are never all the same value. Which of the following equation lead to the correct design for the minimum complexity circuit?

### 49. If A ⊕ B = C, then