What is always in front of you but can’t be seen?

In a competitive exam, each correct answer could win you 10 points and each wrong answer could lose you 5 points. You sat in the exam and answered all the 20 questions, which were given in the exam.
When you checked the result, you scored 125 marks on the test.

Can you calculate how many answers given by you were wrong?

It is an eleven letter word.
The first, second, third and fourth letters form a banquet's name.
The fifth, sixth and seventh letters form a car's name.
The eighth, ninth, tenth and eleventh letters form a mode of transport.

Can you identify what word it is?

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

When monkey rotate the gear, which mark will be hit 1 or 2 ?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

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

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

Imagine you are in a room with no windows or doors. How will you get out?