81 x 9 = 801. What must you do to make the this equation true?

What have one eye but still cannot see?

Can you complete the sequence puzzle?

AR TA GE CA LE VI LI _

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

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

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

If Bihan is 10, Anirudha is 20, and Kim and Seal are both 5, but Rikold is 10, how much is Kenniger by the same trend?

How can a man go eight days without sleep?