Can you find a seven digit number which describes itself. The first digit is the number of zeros in the number. The second digit is the number of ones in the number, etc. For example, in the number 21200, there are 2 zeros, 1 one, 2 twos, 0 threes and 0 fours.

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

I am not a bull but I have horns.
I am not an ass but I have a pack saddle.
Wherever I go, I leave silver behind me.

Who am I?

In a school, there are four subjects. Seventy percent of students study English, seventy five percent of students study Science, eighty five percent of students study Mathematics and eighty percent of students study Spanish.

Can you calculate the percentage of students that study all four subjects?

Kareena is older than Bipasha. Bipasha is younger than Karishma and younger than Katrina. Katrina is older than Kareena and Alonso, who are older than Karishma.If Alonso and Kareena are twins, who's oldest?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

It's pretty hard to give up.
If you remove a part of it, you will be left with a bit.
Even if you remove another part, the bit still remains.
Remove one more and it still remains.

What is it?

Count the number of triangles in the picture below:

Why is a river so rich ?

With the help clues provided in the image, can you find the 5 digit key?