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?

Buy me, smell me or deliver me, I do not change.

Who am I?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Find three numbers such that

* When we multiply three numbers, we will get the prime numbers.
* The difference between the second and the first number is equal to the third and second.

A mathematics teacher took exams for his students. Out of the total students, 25% passed both the tests included in the exam. However, only 42% were able to clear the first test.

Can you find out the percentage of those students who passed the first test and also passed the second test?

You can see it everyday, But cannot touch it at will. What is it?

You have three orange, two pink and five purple balls in the drawer beside your bed. There is no electricity and the room is entirely dark. How many balls must you take out to ensure at least one ball of each colour at least?

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

There's one "sport" in which neither the spectators nor the participants know the score or the leader until the contest ends.

What is it?

Can you calculate the probability of getting a sum of six when a dice is thrown twice?