medium · GMAT Quant
A digital security panel requires a 4-digit code using only the numbers 1, 2, and 3. To prevent easy pattern guessing, the code cannot contain the same digit three times consecutively.
How many valid security codes can be generated?
- 66
- 81
- 78
- 54
- 72
Sign up free to see the explanation and track your rank →
More GMAT Quant practice
- Including both endpoints, how many distinct integer price points are in this range?
- Which of the following expressions must result in a positive value?
- Which property of arithmetic justifies that first step?
- Which of the following must also be an even integer?
- Which of the following inequalities correctly represents this range?
- Which of the following includes the number 0?
- How many unique meal combinations can a customer create?
- What is the probability that the lightbulb is functional?