What is the longest word in the dictionary?

Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

Can you count the number of squares in the given picture?

Using the clues below, what four numbers am I thinking of?

The sum of all the numbers is 31.
One number is odd.
The highest number minus the lowest number is 7.
If you subtract the middle two numbers, it equals two.
There are no duplicate numbers.

You need to arrange three 7 and mathematical symbols to form number 1?

What is the end of everything?

You measure my life in hours
I serve you by expiring
I vanish faster when I am thin
and slower when I am thick
The wind is my energy
What am I?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

During an interview, the interviewer ordered hot coffee for the candidate to relieve the stress. The coffee was kept before him. After a minute, the interviewer asked him, 'What is before you?' He replied 'Tea'.

The candidate was selected immediately. Why?

What am I?