What begins with T, ends with T, and has T in it?

Assume there are approximately 5,000,000,000 (5 billion) people on Earth. What would you estimate to be the result, if you multiply together the number of fingers on every person's left hand? (For the purposes of this exercise, thumbs count as fingers, for five fingers per hand.) If you cannot estimate the number then try to guess how long the number would be.

What is the longest word in the dictionary?

On the dull night when the blonde was dozing, she heard an odd clamour and she saw that there was a bizarre man with a gun simply outside her home. So she raced to the telephone to call the police, however, she can't dial 911. Why?

Find the missing letter in the last circle logically in the given below picture.

If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

A horse was tied to a rope 5 meters long and the horses food was 15 meters away from the horse. How did the horse reach the food?

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

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

What number divided by 4 is the same as that number minus 4?