Solution:

Because they were all married and not single.

Solution:

If you take the first letter , rest become palindrome

Solution:

10 miles
Speed us 10miles/hour

Solution:

Take a bottle of drinks from the "whiskey and coke bottles" box.

If there is a whiskey bottles then you know that is the "whiskey bottles" box since ALL THE boxes are labeled incorrectly.

This means the box marked "whiskey bottles" must be "coke bottles" and the box marked "coke bottles" must be "whiskey and coke bottles".

Solution:

Name of a Person

Solution:

He can sleeps at night :-)

Solution:

Liquid state

Solution:

51 and 15.
42 and 24.
60 and 06.

Solution:

There are 24 hours in a day and 26 Letters. Each letter is allotted one hour. Hence, letter Y and Z could not be interviewed because both exceeded the 24 hours Standard Time. Letter Y and Z are 25th and 26th respectively.

Solution:

Charcoal