What is the Surname of Barbie Doll?

If 24H in a D => 24 hours in a day.
What does "64S on CB" stand for?

The teacher told the student that if he told a lie then he will be expelled from school and if he told the truth then he still is expelled from school.

What can a student say to prevent his being expelled from school?

Can you count the number of matches in the picture below ?

What does this Rebus Picture means ?

Spot the cat in the picture below

Known by all without exception, Forever here, for your protection, Sometimes strong, sometimes weak, Right after the night I come - hot and chic. And while millions of miles away, I always get to you, I find my way. No life around could do without me, Can you guess what I might be?

There once were seven dwarfs who were all brothers. They were all born two years apart. The youngest dwarf is seven years old. How old is his oldest brother?

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?