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

What Word am I Looking For ?

While house hunting in London, I came across a very good leasehold property Discussing the lease the landlady told me:

'The property was originally on a 99 years lease and two-thirds of the time passed is equal to four-fifths of the time to come. Now work it out for yourself and see how many years are to go!

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?

Who is that with a neck and no head, two arms and no hands? What is it?

Count the number of triangles in the picture below:

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?

You can see it everyday, But cannot touch it at will. What is it?

John was so frustrated to be the suspect of being a sleeper terrorist that he shoot himself right between the eyes with a revolver in his toilet. The revolver and the bullets were accurate. Minutes later John walks out of the toilet unharmed.
How can this be possible?

I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?

Which number should replace the question mark?