If two's company, and three's a crowd, then whats four and five ?

Find The Next Number in this series.
1, 2, 6, 42, 1806 ?

Solve The below Equation:

ALFA + BETA + GAMA = DELTA

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

Find the missing letter in the last circle logically in the given below picture.

You find yourself in a strange place guarded by two guards.One of the guard always say truth while other always lies.You don't know the identity of the two.You can ask only one question to go out from there. What should you ask?

Can you count the number of squares in the given picture?

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?

What does does this rebus picture means ?

A plane crashed between the border of Mexico and America. Where do you bury the survivors?