Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?

Make a sentence consisting of three words that have the whole alphabet.

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Only Highly Attentive Can Spot The Ladder In This Library In 7 Seconds! Can You?

What is the next number?

77, 49, 36, 18 ?

John is the son of Jacob.
So,
Jacob is the_____of John's father?

Your last good ping-pong ball fell into a narrow metal pipe embedded one foot deep in concrete.
How can you get it out undamaged, if all the tools you have are your tennis paddle, shoe laces, and plastic water bottle, which does not fit into the pipe?

Can you write down eight eights so that they add up to one thousand?

Which country gets ill every time?

What does this rebus riddle mean?