Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

Find the missing number in the image below.

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

If,

Akriti = 631
Levis = 521
Sroti = 521
Aneel = 533
Then,
Sunil =?

There are a hundred statements.

First person says: At least one of the statements is false.

Second person says: At least two of the statements is false.

Third person says: At least three of the statements are false.

Fourth person says: At least four of the statements are false.

..

..

..

Hundredth person says: At least a hundred of the statements are false.

Analysing it, how many statements do you think are false and how many are true?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Find The Missing Number In the Sequence.
6 25 64 ? 32 1

The host of a game show offers the guest a choice of three doors. Behind one is an expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?