Question

Winnie wrote the following riddle: I am a number between 60 and 100. my ones digits is two less than my tens digit. I am a primer number. what number does winnie's riddle describe? winnie's friend Marco guessed that her riddle was about the number 79. why can't 79 be the answer to winnie's riddle?

Answer 1

He's wrong because 9 is two more than 7, not two less.

Answer 2

79 isn't the answer because the ones digit has to be 2 less than the tens digit, not 2 more!