58.9k views
1 vote
A combination lock requires a user to select three numbers to unlock it, where all three numbers are between 1 to 30, inclusive, and numbers can be used more than once. What is the probability someone can guess the correct combination given 100 attempts?Write your answer as a fraction.

User Darkpbj
by
7.4k points

1 Answer

1 vote

Solution:

Note that you can repeat numbers.

3 numbers between 1 to 30 including 1 and 30.

that means (30-1)+1=30 numbers.

3 slots that can be repeated, so there is the following number of combinations:


30^{3\text{ }}=\text{ }27000

in 100 attempts, that is a 100/27000=1/270 chance or about 0.37% chance. We can conclude that the correct answer is:


(100)/(27000)\text{ = }(1)/(270)\text{ }

User Esthrim
by
6.3k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.