Best riddles for teens

simplecleanlogicinterview

You are blindfolded and 10 coins are place in front of you on table. You are allowed to touch the coins, but can't tell which way up they are by feel. You are told that there are 5 coins head up, and 5 coins tails up but not which ones are which. How do you make two piles of coins each with the same number of heads up? You can flip the coins any number of times.
Make 2 piles with equal number of coins. Now, flip all the coins in one of the pile. How this will work? lets take an example. So initially there are 5 heads, so suppose you divide it in 2 piles. Case: P1 : H H T T T P2 : H H H T T Now when P1 will be flipped P1 : T T H H H P1(Heads) = P2(Heads) Another case: P1 : H T T T T P2 : H H H H T Now when P1 will be flipped P1 : H H H H T P1(Heads) = P2(Heads)
83.74 %
34 votes
logicsimple

You die and the devil says he'll let you go to heaven if you beat him in a game. The devil sits you down at a perfectly round table. He gives himself and you an infinite pile of quarters. He says, "OK, we'll take turns putting one quarter down, no overlapping allowed, and the quarters must rest flat on the table surface. The first guy who can't put a quarter down loses." You guys are about to start playing, and the devil says that he'll go first. However, at this point you immediately interject, and ask if you can go first instead. You make this interjection because you are very smart and can place quarters perfectly, and you know that if you go first, you can guarantee victory. Explain how you can guarantee victory.
You place a quarter right in the center of the table. After that, whenever the devil places a quarter on the table, mimic his placement on the opposite side of the table.. If he has a place to place a quarter, so will you. The devil will run out of places to put a quarter before you do.
83.67 %
51 votes
cleansimplelogic

I heard of an invading, vanquishing army sweeping across the land, liquid-quick; conquering everything, quelling resistance. With it came darkness, dimming the light. Humans hid in their houses, while outside spears pierced, shattering stones walls. Uncountable soldiers smashed into the ground, but each elicited life as he died. When the army had vanished, advancing northward, the land was gree and growing, refresh.
Rainstorm.
83.67 %
51 votes