Find an omnipotent key (a number) that can open four locks using the following clues:
(1) The first lock is an even number.
(2) The second lock is a number whose factors add up to 42.
(3) The third lock is a multiple of 2 and 5.
(4) The fourth lock is a double digit.
What is the number on the omnipotent key?
Solution to the Problem:
The number on the omnipotent key is 20.Lock #1: The number could be 0, 2, 4, 6, 8, 10, 12, ...
Lock #2: The number must be either 20, 26, or 41 from the table below:
Lock #3: The number must be a multiple of 10: 10, 20, 30, 40, 50, 60, ...
Lock #4: The number must be 10, 11, 12, 13, ... 99.
The problem could be solved with just 2 clues: Lock #2 and Lock #3.
Correctly solved by:
| 1. Anna Vice and Eliza Sheffield | Tuscaloosa, Alabama |
| 2. Brijesh Dave | Mumbai City, Maharashtra, India |
| 3. SreeRoopa Sankararaman | Singapore, Singapore |