You can't think for long before solving this easy puzzle. There is a small room. Four cats are sitting on all the four corners of that room. Three cats are sitting opposite to each of the cats and one cat is sitting at tail of each cat. Calculate the number of cats in the room.
There is a lake with shores A and B. Two motorboats M and N are standing on the opposite sides (A and B respectively). M leaves A and N leaves B and start moving with constant speeds. They meet for the first time 500 yards away from A. After touching the shores, they return back to the previous shore point without taking any break. This time they meet at 300 yards away from B. Can you determine how wide the lake is? What is the relation between the speeds of boats?
There is a box in which there are 20 black chocolates and 16 white chocolates. You take out two chocolates at one time. If both are of same type, you add a black chocolate otherwise you add a white chocolate. You keep repeating like this till there is only one chocolate left in the box. Which type of chocolate will be left in the last? Also, suppose you begin the same process with 100 black and 93 white chocolates. Which chocolate will be left at last then?