John left on a horse on Thursday , was gone for two days, and came back on Thursday after completing his work. How did that happen?

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

What is the difference between a jeweller and a jailer?

We know that money can be names differently for the purpose it is used for. Some of the examples of money given at following places or for following activities:

In temple = Daan
In school = Fees
During marriage = Dowry
For divorce = Alimony
Paying government = Tax
In court = Fine
Employer to employee = Salary
To kidnappers = Ransom
For illegal reason = Bribe
To civil servant retirees = Pension

Do you know what do we call the money a husband gives to his wife?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

Can you name four days which start with the letter 'T'?

He loves to dance, twist and prance, he shakes his tail, and as a way he sails, wingless he flies into the sky. What is he?

Where do fish keep their money?

Prove that the below maths equation is true.

8 + 8 = 91

Take number 1000 and then add 20 to it.
Now add 1000 one more time.
Now add 30.
Now add 1000 one more time.
Now add 40.
Now add 1000 one more time.
Now add 10.

What is the total?