Microsoft Interview Puzzle

5 Pirates Fight for 100 Gold Coins Puzzle

Puzzle: There are 5 pirates in a ship. Pirates have hierarchy C1, C2, C3, C4 and C5.C1 designation is the highest and C5 is the lowest. These pirates have three characteristics : a. Every pirate is so greedy that he can even take lives to make more money.  b. Every pirate desperately wants to stay Read More →

Crossing the Bridge Puzzle

Crossing the Bridge riddle

Puzzle: Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: Read More →

Blind bartender’s problem


Problem: Four glasses are placed on the corners of a square table. Some of the glasses are upright (up) and some upside-down (down). A blindfolded person is seated next to the table and is required to re-arrange the glasses so that they are all up or all down, either arrangement being acceptable, which will be Read More →

Red and Blue Marbles Puzzle

Puzzle: You have two jars, 50 red marbles and 50 blue marbles. You need to place all the marbles into the jars such that when you blindly pick one marble out of one jar, you maximize the chances that it will be red. When picking, you’ll first randomly pick a jar, and then randomly pick Read More →

The Fox and The Duck Puzzle

duck and fox puzzle

Problem: This is the classical puzzle asked in microsoft interview A duck, pursued by a fox, escapes to the center of a perfectly circular pond. The fox cannot swim, and the duck cannot take flight from the water. The fox is four times faster than the duck. Assuming the fox and duck pursue optimum strategies, Read More →

8 Balls Puzzle

8 ball puzzle

Problem: You have 8 balls. One of them is defective and weighs less than others. You have a balance to measure balls against each other. In 2 weighing, how do you find the defective one? Solution: Defective ball is light Make three Groups G1 – 3 balls G2 – 3 balls G3 – 2 balls First weight- Read More →

100 Prisoners and a Light bulb


Problem: There are 100 prisoners are in solitary cells, unable to see, speak or communicate in any way with each other. There’s a central living room with one light bulb, the bulb is initially off. No prisoner can see the light bulb from his own cell. Everyday, the warden picks a prisoner at random, and Read More →

25 horses and 5 lanes

25 horse and 5 lanes puzzle

Problem: There are 25 horses and 5 lanes. You have no idea about which horse is better than other. Find in minimum possible races, the first three fastest running horses. Solution: We will have 5 races with all 25 horses Let the results be u1,u2,u3,u4,u5 v1,v2,v3,v4,v5 x1,x2,x3,x4,x5 y1,y2,y3,y4,y5 z1,z2,z3,z4,z5 Work through a process of elimination: Read More →