A few friends are enjoying their sea voyage in a boat full of apples. On the way, they felt hungry and thus decided to eat the apples. Together, they ate two dozen of apples. When they have eaten the apples, will there be any change in the water level?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

Can you fill the blank with the correct number?

6 30 870 756030 _____

I cannot talk, but I always reply when spoken to. What am I?

Imagine a box with two cogwheels, one big with 24 teeth and one small with 8 teeth. The big one is firmly attached to the center of the box which means it does not turn or move while the small one rotates around the big one.

How many times do you think that the smaller wheel will turn compared to the box when it turns once around the big one?

By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

A beggar on the street can make one cigarette out of every 6 cigarette butts he finds. After one whole day of searching and checking public ashtrays the beggar finds a total of 72 cigarette butts. How many cigarettes can he make and smoke from the butts he found?

When we see 2 but call 10?

What happened when the wheel was invented?