Before Mount Everest was discovered, what was the highest mountain in the world?

Which tank will fill first?

Before the start of the car race, John and Jacob have the same amount of fuel in their car. With this fuel, John can drive for 4 hours while Jacob can drive five hours.
After a time they realize that the amount of fuel left in John's car is 1/4th of the fuel in Jacob's.

For how long they are racing?

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?

A woman named Maria was at the funeral of her mother. She met a nice young man that she had never seen before and after the service, they spent a bit of time together. Then she got busy and didn’t get his name or phone number before he left. She tried to find him, but no one knew who he was or how to contact him. A few weeks later, Maria’s older sister dies and the police suspect murder. Who killed the sister?

In the addition below, all digits have been replaced by letters. Equal letters represent equal digits and different letters represent different digits.
ABCABA
BBDCAA
ABEABB
ABDBAA
------- +
AAFGBDH
What does the complete addition look like in digits?

How many times do a clock's hands overlap in a day ?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?

What can run but never walks, has a mouth but never talks, has a head but never weeps, has a bed but never sleeps?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?