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?

The answer is 76.  If it were a multiple of 3 it also has to be a multiple of 4 and 6 (otherwise the ranges don't match up, which is impossible, given the range for multiples of 3.  If it were a multiple of 6 it would be a multiple of 3.  So it is not a multiple of 6.  But it must be a multiple of 4, else it would have to be in two separate ranges, which is impossible.  So the only number possible is 76. 

Posted by Ron on 2004-09-24 12:23:02