PuzzlersWorld.com

  • Hacker Puzzle
  • Interview Puzzles
  • Number Puzzles
  • Maths Puzzles

Mathematical Puzzle

Guess the pincode

June 24, 2013 by puzzler 3 Comments

A person forgot his 5 digit pin code, but he remembers some hints.

  1. 1st digit is square of 2nd digit.
  2. Sum of 2nd and 3rd digit makes 10.
  3. 4th digit is 2nd digit+1.
  4. Sum of 5th and 3rd digit makes 14.
  5. Sum of all 5 digits = 30

Can you guess the person’s pin code from above hints ?


See AnswerHide Answer
Pin code is 93747.
How?
Lets assume second digit is x, then first digit should be x^2 and fourth digit should be x+1.

also assume, 3rd digit is y then 5th digit should be 14-y.
So the number will look like this:-
<x^2><x><y><x+1><14-y>

As we also know the sum of all digits, we can say

x^2 + 2x +1 +14 = 30
(x+1)^2 = 16
x+1 = 4
x = 3

As sum of 2nd and third digit is 10 => x+y = 10 => y=7
Thus the pin code is 93747.

Checkout more Number Puzzles Tags: Mathematical Puzzle, Solved Puzzles

Girl and the box

June 21, 2013 by puzzler 8 Comments

A girl bought a box when she was 20, She puts $250 in the box on every birthday And her sister takes out $50 from the box on her birthday. Girl died when she was 60 and when the box was opened there were $500 remaining in the box.

How is it possible?
[Read more…]

Checkout more Logical Puzzles Tags: Mathematical Puzzle, medium, Solved Puzzles

How many games to determine a champion?

June 14, 2013 by puzzler 2 Comments

There are 97 baseball team participating in a tournament. The champion is chosen by the usual elimination scheme. That is, all teams are divided into pairs, and two teams of each pair play against each other. The loser of each pair is eliminated, and the remaining teams are paired up again.
How many games must be played to determine a champion?
[Read more…]

Checkout more Logical Puzzles Tags: Easy, Mathematical Puzzle, Solved Puzzles

0.999… = 1 #55

June 7, 2013 by puzzler Leave a Comment

0.9999999…….. = 1, true or false?

0.999.... = 1, Right or Wrong?

0.999…. = 1, Right or Wrong?


See AnswerHide Answer

Its Right, yes 0.999 followed by infinite 9’s is equal to 1.

Proof 1 for 0.999… = 1

x = 0.999...
10x = 9.999...
10x - x = 9.999... - 0.999...
9x = 9
x = 1

Proof 2 for 0.999… = 1

1/3 = 0.333...
3x(1/3) = 3x(0.333...) = 0.999...
1 = 0.999...

Checkout more Number Puzzles Tags: Mathematical Puzzle, medium, Solved Puzzles

What is the next number in sequence? #54

June 4, 2013 by puzzler 1 Comment

 

what is the next number in sequence

what is the next number in sequence

See AnswerHide Answer


Next number in the series will be 3263442.
How?
every number in the sequence= (previous number)x(previous number +1)
thus next number in this sequence will be 1806*1807 = 3263442.

Checkout more Number Puzzles Tags: Easy, Mathematical Puzzle, Series, Solved Puzzles

Get number 28 # 53

May 30, 2013 by puzzler Leave a Comment

How you can get number 28 by using following numbers and operators

Numbers: 1, 5, 7 and 8.
Operators: +, -, * and /
You can use ( ) brackets as well.

Rules:-

  1. You can use each number only once.
  2. You can not use 1 and 5 as 15.
  3. You have to use all of the above number mentioned (1,5,7 and 8)


See AnswerHide Answer

There are multiple solutions
Solution 1: (8-5+1)*7 = 28
Solution 2: 7*5 – 8 + 1 = 28

Checkout more Number Puzzles Tags: Easy, Mathematical Puzzle, Solved Puzzles

10 digit number #52

May 28, 2013 by puzzler 1 Comment

Find the 10 digit number satisfying below conditions

Its first digit is the number of occurrence of 0’s in the number.
Second digit is the number of occurrence of 1’s in the number.
Third digit is the number of occurrence of 2’s in the number.
4th digit is the number of occurrence of 3’s in the number.
and so on up to 10th digit(which is number of occurrence of 9’s in the number).

See AnswerHide Answer

Only 10 digit number satisfying these conditions is 6210001000.

Checkout more Number Puzzles Tags: Mathematical Puzzle, medium, Solved Puzzles

Next number in series? #51

May 27, 2013 by puzzler 1 Comment

 

what is next number in this series? 1, 2, 3, 5, 8, ???

what is next number in this series? 1, 2, 3, 5, 8, ???
Hint: this is a classic and very important series.

See SolutionHide Solution


Next number in the series will be 13.
How?
every number in this series is sum of previous two numbers, thus the next number should be 5 + 8 = 13.
This classic and very important series is called Fibonacci series.

Checkout more Number Puzzles Tags: Easy, Mathematical Puzzle, Series, Solved Puzzles

Missing number in series #45

May 2, 2013 by puzzler 3 Comments

What is the missing number in this series

1,16,36,__,81,100,144

Tried enough already?
See SolutionHide Solution
Series is the square of non prime numbers, 12, 42, 62, 82, 92, 102, 122. these are square in sequence excluding the prime numbers 2,3,5,7 and 11. Thus the missing number in series should be 82=64.

Checkout more Number Puzzles Tags: Easy, Mathematical Puzzle, Series, Solved Puzzles

Submit your Puzzle

You may also like

    Categories

    • Aive hi Puzzles
    • Akbar and Birbal
    • Alphabetical Puzzles
    • Bollywood Puzzles
    • Google Code jam
    • Hindi Riddles
    • Interview Puzzles
    • Interview Questions
    • Logical Puzzles
    • Malayalam Puzzles
    • Maths Puzzles
    • Miscellaneous
    • Number Puzzles
    • Picture Puzzles
    • Riddles
    • Tamil Puzzles
    • Technical

    Social

    • View puzzlersworld’s profile on Twitter
    privacy policy

    Copyright © 2023 · eleven40 Pro Theme on Genesis Framework · WordPress · Log in

    • Hacker Puzzle
    • Logo Puzzles
    • Optical Illusions
    • WhatsApp Puzzles
    • Picture Puzzles
    • Riddles
      ▼
      • Hindi Riddles
    • Bollywood Puzzles
    • Alphabetical Puzzles
    • Aive hi Puzzles
    • Interview Puzzles
    • Logical Puzzles
    • Interview Questions
      ▼
      • Data Structures
      • Binary Tree
      • Algorithms
      • Recursion Questions
      • Amazon Interview Questions
      • Snapdeal Interview Questions
      • Google Code jam
    • Technical
    • Akbar and Birbal
    • Number Puzzles
    • Maths Puzzles
    • Miscellaneous