Eins-Ten < PUZZLES >

 

PuzzleS  ;

1. How will you make 37 out of five 5's using them five times only with any operators.

Ans :  5!/(5+5) + (5x5)

2. Suppose you have a string of 15cm , you want to have minimum numbers of cut for this string

so that you can make any length strings using them.

Ans :  converting 15 to binary (1111) base 2 .  So we have set the 2power0 , 2power1, 2power2 , 2power3 bits i.e 8 ,4,2,1 . So there would be 3 cuts to get the 4 different strings of these sizes and we can make any size till 15. ex 8+4 =12 , 8+4+2=14,2+1=3 , 1,2,1+2=3  etc.

3. There are two doors Right A and Wrong B but not identified, and two guards are standing at those doors. One guard always lies whereas another say always truth. They know about each other behaviors. But you dont know their nature.So how will you identify the right door by asking any

one of them only one time in one chance.

Ans :   Since One Guard will always lie and Another one will always say truth. And they know each others nature. So you can ask any one of them : " Hey Buddy!! Which door will another Guard point, if  i will ask correct door from him?"

Since you dont know their nature , so you can ask anyone unknowingly. There could be two cases .

case 1 : Either you will ask from Guard who says truth , then he would say that another guard will point to B door( Wrong , as another Guard lies so he will not show you correct door).

case 2: Or you will from Guard who lies , then he would say that another guard will point to B door ( He know that another Guard says truth so he will point to correct door A , but this Guard always lies so he will say opposite of that and will point to door B i.e wrong)

for Both cases you got pointed to Wrong door B ,  so you go to another door which would be Correct A.