A girl is twice as old as her brother and half as old as her father. In 50 years, her brother will be half as old as his father. How old is the daughter now?

Can you find a number that lies one third of the distance between 1/3 and 2/3?

A four-digit number (not beginning with 0) can be represented by ABCD. There is one number such that ABCD=A^B*C^D, where A^B means A raised to the B power. Can you find it?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

Can you write down eight eights so that they add up to one thousand?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

Can you find the least possible number such that

If the number is divided by 3, it gives the remainder of 1;
If the number is divided by 4, it gives the remainder of 2;
If the number is divided by 5, it gives the remainder of 3;
If the number is divided by 6, it gives the remainder of 4.

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

How do you go from 98 to 720 using just one letter?