If it took eight men ten hours to build a wall, how long would it take four men to build it?

Can you find the 09 errors in the picture below?

Can you think of a smallest +ve number such that if we shuffle the digits of the number, the new number becomes double the original number?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

What has a ring but no finger?

I have four wings but can't fly.
I express no emotions.
I am found on the exact spot every time you look.
I keep toiling away with a little sound.

Do you know what am I?

Can you solve the below tricky visual equation?

You are given a cube that is made with the help of 10x10x10 smaller cubes summing up to a total of 1000 smaller cubes. You are asked to take off one layer of the cubes.
How many remain now?

The Little ant seems to be always confused. Do you know why?