1. 1113213211 After the first line, each line describes the previous line:One One
One Two, One One
(and so on...)
2. He said, "You'll sentence me to six years in prison." If it was true, then the judge would have to make it false by sentencing him to four years. If it was false, then he would have to give him six years, which would make it true. Rather than contradict his own word, the judge set the man free.
3. Fill the 3-gallon container with oil and pour it into the 5-gallon container. Then fill the 3-gallon container again and use it to fill the 5-gallon container the rest of the way. One gallon will be left in the 3-gallon container.
4. Five. There are only four colors, so five socks guarantee that two will be the same color.
6. It's part of his job - he's a justice of the peace.
7. Seven. The four daughters have only one brother, making five children, plus mom and dad.