I'm thinking of a number.
- if it is not a multiple of 4, then it is between 60 and 69
- if it is a multiple of 3 it is between 50 and 59
- if it is not a multiple of 6 it is between 70 and 79.
What is the number?
76!
no common multiple of 6 and 4 is between 50 and 59 and if it is NOT a multiple of 4, then it MUST be between 50 and 59, so that means that it is between 70 and 79. The only multiple of four between 70 and 79 that is not a multiple of 12 (LCM of 3 and 4) is 76.