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?

You have a basket containing ten apples. You have ten friends, who each desire an apple. You give each of your friends one apple.
Now all your friends have one apple each, yet there is an apple remaining in the basket.
How?

What will you call your mother's brother's brother-in-law?

Can you fill the blank with the correct number?

6 30 870 756030 _____

For this puzzle, you might have to find logic in something illogical. But hey, it's fun and a healthy little break from your strenuous puzzle-solving sessions.

Can you decipher the meaning in the following cluster of letters?

ITIT,NCENTCENT

What has many keys but can’t open a single lock?

If all Goats are Sheep and all Sheep are Deers, are all Deers Goats ?

What has 13 hearts but no other organs?

How can you make number one disappear by adding something to it?

What can you hold in your right hand, but never in your left hand?