John asks Tom:
"Is your house number bigger than 50?"
Tom answers him, but he lies. (John doesn't know that he's lying) John continues to ask:
"Is your house number a multiple of 4?"
Tom answers and again, he lies. Then John asks:
"Is your house number the square of an integer?"
Tom answres, but this time he tells the truth. Finally, John asks:
"Is the first digit of your house number 3?"
After Tom answers (we don't know if he lied or not) John declares Tom's house number, but he is wrong! What is Tom's house number?