Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

On a special event at the prison, 5 prisoners John, Jacob, Krist, Tang, and Dang given a chance to go to a sauna and can bring one thing with them.

Following are the things that the prisoners bring with them.
John: A soda
Jacob: Thermos
Krist: Book named "How to kill"
Tang: A Walkman
Dang: Harmonica

Since it is a Sauna, no one can see each other. After a while When the steam is switched, Tang was found dead and there was blood all around.
J Bond was called and he instantly come to know who can be the murderer. How?

What word does this rebus represent?

meta meta
meta meta

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

Find the next number in the series below

21 32 54 87 131 ?

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

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

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In a guessing game, five friends had to guess the exact numbers of apples in a covered basket.
Friends guessed 22, 24, 29, 33, and 38, but none of the guesses was correct. The guesses were off by 1, 8, 6, 3, and 8 (in random order).

Can you determine the number of apples in a basket from this information?

A woman lives in a skyscraper thirty-six floors high and is served by several elevators which stop at each floor going up and down. Each morning she leaves her apartment and goes to one of the elevators. Whichever one she takes is three times more likely to be going up than down. Why?