By removing one matchstick and adding one matchstick, can you convert the word "ZOO" to an animal name?

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

That attorney is my brother, testified the accountant.

But the attorney testified he didn't have a brother.

Who is lying?

Jack have ten pairs of black socks, eight pairs of white socks and seven pairs of green socks. Everything is mixed in a draw. As there is no light he were not able to identify the colour of the socks. How many of the socks did he want to take to match one pair

How can you drop a raw egg from a height onto a concrete floor without cracking it?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

I want to fill my bucket using both cold and hot water.
I have two taps for both cold and hot water. The hot water tap fills the bucket in exact 6 hours and the cold water tap fills the bucket in exact 4 hours.
I turn both of them simultaneously but I forgot to turn off another tap which removes the water out of the bucket. This tap can empty the bucket in 12 hours.

How Long will it take to fill the bucket?