Difficulty: Easy
Correct Answer: 128
Explanation:
Introduction / Context:Truth tables enumerate all possible input combinations for a logic function. For n binary inputs, there are 2^n combinations. This question checks the ability to compute the size of the truth table for a 7-input logic gate (AND, but the count depends only on n).
Given Data / Assumptions:
Concept / Approach:The count of binary words of length n is 2^n. Thus, for n = 7, we have 2^7 total rows. This is independent of the logic function; AND, OR, XOR etc. share the same number of rows for the same n.
Step-by-Step Solution:
Use formula: total rows = 2^n. Compute: 2^7 = 128. Select 128 as the answer.Verification / Alternative check:List sizes grow as 2, 4, 8, 16, 32, 64, 128 for n = 1…7, confirming 128 for n = 7.
Why Other Options Are Wrong:
64 = 2^6; 32 = 2^5; 16 = 2^4; these correspond to fewer inputs. “None” is incorrect because 128 is valid and present.Common Pitfalls:Using 2*n instead of 2^n; confusing number of outputs with number of table rows.
Final Answer:128
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