DIFFICULT RIDDLES

You can carry it everywhere you go, and it does not get heavy. What is it?

Name an eight letter word that has kst in the middle, in the beginning, and at the end.

There was a man who was born before his father, killed his mother, and married his sister. Yet, there was nothing wrong with what he had done. Why?

In a contest, four fruits (an apple, a banana, an orange, and a pear) have been placed in four closed boxes (one fruit per box). People may guess which fruit is in which box. 123 people participate in the contest. When the boxes are opened, it turns out that 43 people have guessed none of the fruits correctly, 39 people have guessed one fruit correctly, and 31 people have guessed two fruits correctly.

The Question: How many people have guessed three fruits correctly, and how many people have guessed four fruits correctly?

What is the difference between a school boy studying and a farmer watching his cattle?

Marking mortal privation, when firmly in place. An enduring summation, inscribed in my face.

What am I?

A prisoner is told "If you tell a lie we will hang you; if you tell the truth we will shoot you." What can he say to save himself?

A boy has as many sisters as brothers, but each sister has only half as many sisters as brothers.

How many brothers and sisters are there in the family?

In 2000, a 40-year-old doctor told his son that when a little boy he decided to be a doctor by seeing a internet web site about performing a heart transplant on a puppy with a defective heart so that the puppy would live a normal life. I then thought that I would be a doctor so that I could help people in a similar way. What is the defect in this story?

My first is a creature whose breeding is unclear. My second, a price you must pay. My whole can be found in the river of Time and refers to events of today. What am I?