What is common among 11, 69, and 88?

We have shown you a regular water barrel as below. Without using any measuring device can you check if the barrel is more than half-filled or less than half-filled?

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

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

What can you catch but never throw?

John said, "If yesterday was tomorrow, today would be Friday."

When did John make this statement?

What does a man do only once in his lifetime, but women do once a year after they are 29?

A mathematician couple was having a Frappuccino in Starbucks sitting opposite to each other. Suddenly the guy noticed the text written on the paper in front of them and exclaimed that it was wrong. The girl denied it and said it is appropriate. Both are correct. What is written on the paper?

No one wants to have it, but if one got it, he does not want to lose it. What is It?