A simplex lock uses only numbers from 1- 5 but this safer lock contains 10 numbers from 0 to 9. The rules are the same, we can press more than 1 number at once, we can’t use the same number in the password. If the password contains 4 numbers, then there will be 15. 750 combinations, while a normal lock will only contain 10. 000 combinations from 0000 – 9999. Actually, we can do it using bigger numbers for safety but 15. 750 combinations would be hard enough for someone to crack it. First, we need to divide it into several cases according to the numbers of each press. To count it we need to use permutation and combination. In the first case we use permutation because 1 2 3 4 are not the same with 4 3 2 1. In the second, third, fourth there is a press where we press 2 numbers at once. Therefore, we use both combination and permutation here because 1 2 34 is same with 1 2 43.The fifth and sixth case we also use both because 1 234 is same with 1 324. The seventh case we use combination twice because 12 34 is same with 21 43. The last case which is the eight we use combination because 1234 is same with 4321. After we get the number of combinations in each case we can add it all together.Hence, we get the total number of the combinations. Result and AnalysisThis safer lock is a 4 numbered lock can have 15. 750 combinations which is shown by the table. It has proven that it is correct if this lock has more combinations than a normal lock. It has more combinations because we can press 2 or more numbers at one time, it will add about 2 times the normal one. To have more combinations we could use the same number again which can cause the number of combinations become more than 30. 000. Conclusion and Recommendation From here, we can conclude that this safer lock is safer than a normal lock even though there is only a little bit of changes in the rules. If each time we use 3 seconds to try 1 combination then it would take 47. 250 seconds which is 13,125 hours or a half day. So, it is very recommended to use this lock to make our things inside our luggage and also our house safer.