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A bank vault has three locks with a different key for each
Chapter 4, Problem 4.20(choose chapter or problem)
A bank vault has three locks with a different key for each lock. Each key is owned by a different person. To open the door, at least two people must insert their keys into the assigned locks. The signal lines A, B, and C are 1 if there is a key inserted into lock 1, 2, or 3, respectively. Write an equation for the variable Z which is 1 iff the door should open.
Questions & Answers
QUESTION:
A bank vault has three locks with a different key for each lock. Each key is owned by a different person. To open the door, at least two people must insert their keys into the assigned locks. The signal lines A, B, and C are 1 if there is a key inserted into lock 1, 2, or 3, respectively. Write an equation for the variable Z which is 1 iff the door should open.
ANSWER:Step 1 of 4
To open the door,at least two keys should be inserted into the correct lock,that means two out of three signal lines must be 1,when the door opens the variable, 
The corresponding output function is
To find the equation for the output function,we will write it in the form of minterms and simplify.