Maths Puzzles

 The puzzle was Here is a numeric lock. 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?   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....

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

 This puzzle is about leap years. Copied straight from reddit  George’s 30th birthday will be on the last leap year of this decade.  Nicole’s 21st birthday was on the last leap year with an odd digit in it.   What are the years of birth of George and Nicole? 

The number must start with a 3 because it is between 290000 and 310000 and 2 is not an odd number - all digits are odd. The number also ends with.  The third digits is number of fingers on your hand. So 5. 3rd, 4th and 5th digits are consecutive odd numbers in ascending order - so they are 579 Second digit is 4th digit - 2 = 7-2 = 5 So we have our answer :  355793 What about the bonus question?  So if the ant travels x inches on first day, it travels x/3 inches on second day and x/3/3 inches on third day. The total distance is 78 x + x/3 + x/9 = 78  13x/9 = 78 x = 78 * 9/13 = 54 inches. First day it traveled 54 inched. Second day 54/3 = 18 inches and third day 18/3 = 6 inches. Total is 54+18+6=78 Note : The original question has distance as 76 inches. But that gives us a fractional value? Any other answers for 76 as total?

 Yes. Re-read the question now. what has w h a t - four letters. sometimes has  nine letters and never has five letters. Yes, a silly puzzle. But we can solve it. Which is good.

 Non stop consumption of Netflix and mobile games has dumbed down my brain. It happens to the best of us. Even to Einstein - the inventor of gravity ;) So I am of course discussing a very simple number puzzle - which does not involve any kind of analysis. So that we all solve it and feel better about ourselves.  It is a 6 digit number between 290000 and 310000. All the digits are odd. The first and the last digits are same. The second digit is obtained by subtracting 4th digit by 2. 3rd, 4th and 5th digits are consecutive odd numbers in ascending order. The number of fingers in your hand is the third digit.  What is the the number?   I am certain that all of you get the answer in no time.  As soon as you finish that puzzle, here is a bonus puzzle.  An ant has traveled 78 inches in 3 days. Each day it travels one third of the previous day. What distance does it travel on first day?

 This one is actually silly but interesting. What has four letters, sometimes has nine, but never has five?