Who Did It: Murder in A Family of 4

One evening there was a murder in the home of married couple, their son and daughter. One of these four people murdered one of the others. One of the members of the family witnessed the crime.The other one helped the murderer.

These are the things we know for sure:

1. The witness and the one who helped the murderer were not of the same sex.

2. The oldest person and the witness were not of the same sex.

3. The youngest person and the victim were not of the same sex.

4. The one who helped the murderer was older than the victim.

5. The father was the oldest member of the family.

6. The murderer was not the youngest member of the family.

Who was the murderer?

   
Find out the murderer here!

Source 

Roles of Family Members

What was the case?

From (6), we know the youngest one wasn't the murderer. Clue (3) suggests youngest wasn't the victim & (4) hints that youngest wasn't helper too. Hence, youngest must be witness.

So possibilities of others' role are listed in table below.

 

From (2), the witness had opposite sex than the oldest & from (5), we know father is the oldest. So witness must be daughter.

From (4), murderer was older than victim & since father is oldest he can't be victim. So last 2 possibilities are eliminated.

Challenge Of Crossing Desert

Mr. Rawat wishes to cross a the Sahara desert.

It requires 6 days to cross.

One man can only carry enough food and water for 4 days.

What is the fewest number of other men required to help carry enough food for Mr. Rawat to cross ? 

He need only few helpers in the case!

Source

Efficient Way To Cross Desert

What's the challenge?

Mr. Rawat should take 2 helpers - let's name them as A & B.

Let 1 be the unit of food & water that is required for 1 day. So all are going to carry 4 units of food & water.

On the day 1, Mr. Rawat, B & A himself take the food & water from A. Then A will left with only 1 unit & to survive he should go back. In 1 day, he can consume that 1 unit of food & water & travel back to the origin.

On the day 2, Mr. Rawat & B consume 2 units food & water of helper B. Now helper B has to move back to origin with 2 units of food & water in 2 days. Again he can easily go back in 2 days covering distance traveled by him in 2 days of forward journey.

Now Mr. Rawat has 4 units of food & water which he can use in his 4 day's journey of crossing Sahara desert.