Logic
A farmer has 17 sheep. All but 9 run away. How many sheep does he have left?
9 sheep
What has a face and two hands, but no arms or legs?
A clock
A woman has two sons who were born in the same hour on the same day of the same year. They are not twins. How is this possible?
They are two of a set of triplets.
What occurs once in a minute, twice in a moment, and never in one thousand years?
The letter "m."
You have two ropes and a lighter. Each rope takes exactly one hour to burn but doesn’t burn evenly. How do you measure 45 minutes?
Light both ends of one rope and one end of the other. When the first rope burns out, 30 minutes have passed; then light the second end of the other rope
You measure my life in hours and I serve you by expiring. I’m quick when I’m thin and slow when I’m fat. The wind is my enemy. What am I?
A candle.