Can you replace the question mark with the correct letter?

6 + 6 + 6 = N
7 + 7 + 7 = E
8 + 8 + 8 = R
0 + 0 + 0 = ?

By using 'because' continuously three times, can you make an English statement ?

A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

Why 1729 is a magic number? Answer Logically.

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

On the dull night when the blonde was dozing, she heard an odd clamour and she saw that there was a bizarre man with a gun simply outside her home. So she raced to the telephone to call the police, however, she can't dial 911. Why?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

Can anyone tell me a word in the English dictionary which has a silent 'z'?

What has many keys but can’t open a single lock?