The below given figure comprises of a pattern through which you can determine the missing letter. Can you push your mind to find the pattern and add the missing letter?

When it is alive we sing, when it is dead we clap our hands. What is it?

How many cubic feet of dirt are in a hole of one foot deep, three feet long, and two feet wide?

Which three-digit number, made of consecutive digits, like 567, is 2 less than a cube and 2 more than a square?

There is a place where if I stand up straight, I will still be considered sideways.

Thomas has missed an excessive number of days of school, so he must meet with Principal Davis. Mr. Davis asks him "Why on Earth have you missed so many days?" Thomas replies "There just isn't enough time for school. I need 8 hours of sleep a day, which adds up to about 122 days a year. Weekends off is 104 days a year. Summer vacation is about 60 days. If I spend about an hour on each meal, that's 3 hours a day or 45 days a year. I need at least 2 hours of exercise and relaxation time each day to stay physically and mentally fit, adding another 30 days. Add all of that up and you get about 361 days. That only leaves 4 days for school." The principal knows Thomas is full of it, but can't figure out why. Where is Thomas going wrong?

A father's child, a mother's child, yet no one's son.

Who am I?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.

A man lives on the fifteenth floor of an apartment building. Every morning he takes the elevator down to the lobby and leaves the building. In the evening, he gets into the elevator, and, if there is someone else in the elevator, or if it was raining that day, he goes back to his floor directly. Otherwise, he goes to the tenth floor and walks up five flights of stairs to his apartment. Can you explain why he does this?

10+10 and 11+11 can give you the same answer.

Explain how?