Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

John’s parents have three sons: Snap, Crackle, and what’s the name of the third son?

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?

Aaron, Brad, Christopher, Danny and Elvis decided to play a game of tiddlywinks. In this game they decided that one win will get 1 point for winning, 0 for losing and 1/2 in case of a tie.

They finished the game in alphabetical order and it was found that the scores were different for each person.

Based on the following two statements, can you find out the result of the individual games?
Brad: No one could finish like me, without a loss.
Elvis: No one played worse than me, I finished without a single win.

What number do you get when you multiply all of the numbers on a telephone's number pad?

Suppose you are a girl candidate and sitting in an interview. Suddenly the interviewer asks you, 'What if one morning you wake up and find out that you are pregnant?

How will you reply to such a question?

It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

If it took eight men ten hours to build a wall, how long would it take four men to build it?