Name a key which is hardest to turn.

Through your logical capabilities, can you make 7 an even?

Count The number of F's in the paragraph below:

"FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED WITH THE EXPERIENCE OF YEARS"

It's pretty hard to give up.
If you remove a part of it, you will be left with a bit.
Even if you remove another part, the bit still remains.
Remove one more and it still remains.

What is it?

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!

Christina has four daughters, and each of her daughters has a brother. How many children does Christina have?

I am an odd number. Take away a letter and I become even. What number am I?

A man wants to cross the pit of fire which is 25 feet in length and he has 2 planks(fire resistant) 19 feet in length. How can he cross the pit of fire alive?

If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

If eleven plus two equals one, what does nine plus five equal?