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

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

When can we add 2 to 11 and get 1 as the correct answer?

I have 50 feet long of cloth, I need to create 50 handkerchiefs each size of 1 foot. I take one minute to cut a 1-foot handkerchief. So how long will it take to cut 50 handkerchiefs?

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?

On one occasion, A Boy collects 71 rupees in form of 20 paise and 25 paise. He collects a total of 324 coins.

Can you tell me how many 20-paisa and 25-paisa he got?

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year. What day is my birthday?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.