How many times can you subtract the number two from the number fifty?

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.

I am a five-letter word and comprises two different vowels and three same consonants. I am so strong that I can spoil your entire work.

Can you find out who am I?

Manish has to secure 40% marks to pass his B.tech final exams.
He got just 40 marks and failed by 40-marks.

What is the maximum marks?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

How many times can you subtract the number 5 from 25?

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

Begin with a word, five letters to my name,
Remove the first and last but I am the same
Take out my middle and still, I remain.
What word am I?

There are five vowels (a, e, i, o, u) in the English language.
Can you tell us a word that contains all these vowels?