What is black when you buy it, red when you use it, and gray when you throw it away?

The product of three consecutive numbers is 7980.
Then the sum of these consecutive numbers would be?

John was running from 40 thieves. John has got 3 gold boxes which weigh as 4kg, 2kg, and 1kg respectively. A witty man asked John to stay with him for seven days in exchange for 1kg gold per day. John needs to stay there for seven days and also do not want to give the witty man any advance. How can John pay for his seven days stay?

Sachin bought a car with a strange 5 digit numbered plate.The water image of the number is 78633 more than my car number. All the digits of car number are distinct.

What is the original number on number plate?

It is raining today at 11:59 am. What is the probability of sunny weather after 72 hours?

What are the next two letters in the following series and why?
W A T N T L I T F S _ _

*Hint: Check Puzzle Title

Can you fill the blank with the correct number?

6 30 870 756030 _____

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?