Puzzle 83 - Ageism

-

I know you have read such  age puzzles a million times. Now I will tell you million one-th puzzle.

But as a repentance,  I am giving out a simple trick to find the square of smaller numbers. With an example. 

 

Let us say you want to find the square of 37. Which is the nearest number you know  the square of? 30?

OK. 30 is 7 below 37. Take a number 7 above 37 too - 44. Now multiply 30 and 44. You get 1320 right. Now square the number 7 - the one you have used to go above and below the number. You get 49. Add this square to 1320. 1320+49 = 1369. Isn't that the square of 37 - find out with your calculator app. 

Use this trick to find the square of 43. 

  • 43 -3 = 40. 
  • 43+3=46.  
  • 40X46 = 1960
  • 32 is 9. Add this to previous product. 1960+9
  • The answer is 1969 - square of 43 is 1969

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 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

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