Puzzle 35 - Solution

-

 The puzzle was

Here is a numeric lock. And here are the results of various number combinations.

  1. 682 - one digit is right and in the right position.
  2. 614 - one digit is right but in the wrong position.
  3. 206 - two digits are right but both are in the wrong positions.
  4. 738 - all digits are wrong.
  5. 380 - one digit is right but in the wrong place
So what is the correct code to open the lock?
 
The correct number is 042.

Now let us see how we get this solution
  • 682 and 614 have common as 6. But first hint says the digit is in right place and second says, it is in the wrong place. So 6 is not the correct digit
  • 206 says two digits are correct but in wrong place. Which means 2 and 0 are correct digits (6 is not correct)
  • 738 says all digits are wrong and 380 says one digit is right but in the wrong place. 7 and 3 and 8 are all wrong. So only 0 is the correct digit. And 0 is not in the third place.
  • 0 is not in the place, it is not in second place (rule 3). So it should be in first place. 
  • 2 is the correct digit and it is in last place.  (rule 1). 
  • One digit in rule 2 must be the correct digit. It is not 6. It is not 1 as 1 is already in the middle position. So digit must be 4. 
  • Our solution is 042

Comments

Post a Comment

Popular posts from this blog

Puzzle 9 : The 4 coins problem

-
 Solution to puzzle 8: Maria is not counting Sundays. So she is not counting 1/7th of days of her age.  That is to say she is only counting 6/7th of her age. 6/7th of her age = 30 Her actual age = 30 X 7/6 = 210/6 = 35 years.  Puzzle 9 : The 4 coins problem  You’re creating a new coin system for your country. You must use only four coin values and you must be able to create the values 1 through 10 using one coin at a minimum and two coins maximum. What 4 coins do you choose, and can you think of a second set of 4 coins that achieves the same goal?
Read more

Puzzle 35 - Open sesame

-
I am writing a post after two months.  Here is a locked question ;) There is a number lock. You have to find the number to unlock it.  And here are the results of various number combinations. 682 - one digit is right and in the right position. 614 - one digit is right but in the wrong position. 206 - two digits are right but both are in the wrong positions. 738 - all digits are wrong. 380 - one digit is right but in the wrong place So what is the correct code to open the lock? Find the solution here
Read more

Puzzle 66 - solution

-
 The question was  What is wrong with this proof ? a=b multiply both the sides by a     --1 a2 = ab  add -b2 to both the side           --2 a2-b2 =ab-b2  factorizing                                --3 (a+b)(a-b) = b(a-b)  divide both the sides by (a-b)    ---4 a+b=b Substituting a with b,              ---5 2b = b Dividing both the sides by b    ---6 2 = 1   The problem is with step 4. When a is equal to b, a-b is zero. You can not divide numbers by zero because division is only defined for non-zero numbers.  
Read more