A swan sits at the center of a perfectly circular lake. At an edge of the lake stands a ravenous monster waiting to devour the swan. The monster can not enter the water, but it will run around the circumference of the lake to try to catch the swan as soon as it reaches the shore. The monster moves at 4 times the speed of the swan, and it will always move in the direction along the shore that brings it closer to the swan the quickest. Both the swan and the the monster can change directions in an instant.
The swan knows that if it can reach the lake's shore without the monster right on top of it, it can instantly escape into the surrounding forest.
A Japanese ship was en route to a mission on foreign seas. The captain of the ship felt tired and thought of taking a bath. He went for taking the shower and removed his diamond ring and Rolex and kept them on the table. When he returned after taking the bath, he found that the ring and watch were stolen.
He called the five members of the crew whom he suspected and asked them what they were doing for the last 15 minutes.
The Italian cook (with a butcher knife in hand): I was in the fridge room getting meat for cooking.
The British Engineer (with a high beam torch in hand): I was working on a generator engine.
The Pakistani seaman: I was on the mast correcting the flag which was upside down by mistake.
The Indian Radio officer: I was trying to make a contact with the company to inform them about our position.
The American navigation officer: I am on night watch, so I was sleeping in my cabin.
Upon listening to them, the captain caught the lying member. Who do you think stole the valuables?
Two friends Smith and Andrew were talking about the bravery of their families. Smith told great stories about his courageous grandfather who fought for Britain in "World War I". Andrew told that his grandfather was so brave that in 1919 just after the war he was honoured with a bravery medal with the words "For our Courageous Soldiers In World War I" embedded into it. Smith knows that his friend is lying. How?
In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?
A bag contains 64 balls of eight different colours. There are eight of each colour (including red). What is the least number you would have to pick, without looking, to be sure of selecting 3 red balls?