Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

The following question it puts forth you:

25 - 55 + (85 + 65) = ?

Then, you are told that even though you might think it's wrong, the correct answer is actually 5!

Whats your reaction to it? How can this be true?

Why is the Hole below a Lock?

Which five letter word can be added at the end of below word to form a
valid word?

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You need to arrange three 7 and mathematical symbols to form number 1?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

For an extra income, John decided to work at a Hotel for one hour daily. The manager offers him that they will pay him $11 after every 11 days.
However, John offered a different proposition to the manager. The offers stand as:
He will be paid just a penny on his first day.
Two pence will be paid on the second day,
Four pence will be paid on the third day.
And so on till the 11th day.

Should the Hotel manager accept his offer?

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?