Puzzle 71 - solution

-

 

The question was

The following characteristics apply to a group of people in a room:

Fourteen are blonds, eight are blue-eyed, and two are neither blond nor blue-eyed. If five of the people are blue-eyed blonds, how many people are in the room?

 

Solution : 

 Let us try to understand this with a diagram


In this diagram

  • a = blue eyed people who are not blond     b - blond people who are not blue eyed
  • c - both blond and blue eyed      d - neither blond nor blue eyed (which is 2)

We know that c = 5. And a+c (blue eyed people)= 8. Which means a  = 8-5 = 3

We also know that b+c = number of blonds  = 14. So b = 14 - 5 = 9

Now total number of people in the party  = a+ b+c+d = 3+9+5+2 = 19

So c is the correct answer.


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