Question

Bob's favorite number is between 50 and 100. It is a multiple of 11, but not a multiple of 2. The sum of its digits is a multiple of 3. What is Bob's favorite number?

Answer 1

99

Explanation:

There are 5 numbers between 50 and 100 that are multiples of 11:

55, 66, 77, 88, 99

Of these, 3 are not multiples of 2:

55, 77, 99

Only one is a multiple of 3:

99