#1 - Good Age Riddle

Lena Dunham , Allison Williams, and Jemima Kirke are 3 daughters of a good mathematician "Geroge".
When I asked George the age of their daughters. He replied "The current age of her daughters is prime. Also, the difference between their ages is also prime."

How old are the daughters ?

Lena Dunham : 2 , Allison Williams : 5 and Jemima Kirke : 7

Age diff : 7-2 is 5 , 7-5 is 2 and 5-2 is 3 which all are prime numbers

#2 - Missing Rs1 Puzzle

I have Rs.50 and i spend in the way below.

Missing Rs1 Puzzle

Adding commutative balance does not make any sense.
Check my next example, where is spend Rs 50 in way below

Spent Balance
10 40
10 30
10 20
10 10
10 0
==============
50 100

So in the puzzle, the number was chosen to confuse readers.

#3 - Find The Thief Riddle

Can you find the thief by just looking at the picture below?

 Find The Thief Riddle

The Lady sitting in the chair has the detector attached to the back of her blouse.

#4 - Correct Dress Probability Problem

A mother bought three dress for her triplets daughters(one for each) and put the dresses in the dark. One by one the girls come and pick a dress.
What is the probability that no girl will choose her own dress?

1/3

Explanation
Assuming D1 is the dress for Sister1, D2 is the dress for Sister2 and D3 is the dress for Sister3.

Therefore the total number of cases are illustrated below.

Sister1 Sister2 Sister3
D1 D2 D3
D1 D3 D2
D2 D1 D3
D2 D3 D1 ..... (1)
D3 D1 D2 .... (2)
D3 D2 D1

In both steps (1) & (2), no one gets the correct Dress.
Therefore probability that no sister gets the correct dress is 2/6 = 1/3

#5 - Hard Missing Number Series

Can you complete below number series by replacing "?" with the correct number.

10 # 10 # 20 # ? # 110 # 300 # 930

45

Pattern goes like
10
10 * 0.5 + 5 => 10
10 * 1.0
+ 10 => 20
20 * 1.5 + 15 => 45(Ans)
45 * 2.0 + 20 => 110
110 * 2.5 + 25 => 300
300 * 3.0 + 30 => 930

#6 - Test Critical Thinking Interview Questio

This is the interview puzzle asked to my friend in an interview of "blackrock".
As shown in the picture below, There is a circular car race track of 10km. There are two cars, we called them Car A and Car B. And they are at the exact opposite end to each other. At Time T(0), Both cars move toward each other at a constant speed of 100m / seconds. As we know both cars are at the same speed they will always be the exact opposite to each other.
Note, at the center, there is a bug which starts flying towards Car A at time T(0). When the bug reaches car B, it turns back and starts moving towards the car A. The speed of bug is 1m/second. After 5hours all three stop moving.
What is the total distance covered by the bug?

As we know bug travels at a constant speed of 1m/seconds
=> in 5 hours
=> 5 * 60 * 60 meters
=> 18km.

#7 - Strange Birthday Puzzle

Today, I celebrated my 32nd birthday but I was born in 1971.
How is this possible ?

I was born in Hospital whose room number is 1971.

#8 - Charity Tennis Match Puzzle

In Dubai at the charity event, Federal and Nadal played exactly five matches. Both wins exactly an equal number of matches.

How is this possible?

They do not plan against each other.

#9 - Find Company Name Pictogram

Can you find company name from the pictogram below?

Find Company Name Pictogram

Microsoft (Mic + Crow + Softy)

#10 - Oldest Riddle Heard

This is the oldest riddle that I have heard.

Once there was a man who is travelling with a Tiger , goat and grass.
He needs to cross the river that can carry the maximum of two i.e Man + one of Tiger goat or grass. But the problem is "If he takes lion with him, the goat will eat grass and if he takes grass with him, the lion will eat goat".

How can he ensure safe delivery of all three?

It can be done in four steps.
1. Men & goat to the other end. Then the man comes back.
2. Man & lion to the other end. Then the man comes back with the goat. 3. Man & grass to the other end. The man comes back alone
4. Man & goat to the other end.

All done.