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

What Word am I Looking For ?

After undergoing a successful eye operation, A blind girl has just boarded a train to her home. The doctor asked her to open the bandages after 3 hours. On her train journey, she opened the bandages and within a fraction of the time she commits suicide by jumping off the train.

Though her operation was successful, Why did she commit suicide?

If,

20 % 5 = 24

21 % 7 = 33

42 % 6 = 67

Then;

66 % 6 = ?

How can you tell a raw egg from a hard-boiled egg?

A shepherd had 18 sheep, out of which, all but ten died.

Can you tell us how many sheep was he left with?

Three cars are driving on a track that forms a perfect circle and is wide enough that multiple cars can pass anytime. The car that is leading in the race right now is driving at 55 MPH and the car that is trailing at the last is going at 45 MPH. The car that is in the middle is somewhere between these two speeds.
Right now, you can assume that there is a distance of x miles between the leading car and the middle car and x miles between the middle car and the last car and also, x is not equal to 0 or 1.
The cars maintain their speed till the leading car catches up with the last car and then every car stops. In this scenario, do you think of any point when the distance between any two pairs will again be x miles i.e. the pairs will be x distance apart at the same time ?

It is always ahead of me yet I can never see it. What is it?

Can you name an animal whose killing cannot be performed without spilling your own blood?

There is something which you can be arrested for attempting but not for successfully completing.

In the given figure, move three matchsticks so that the resulting figure contains two rectangles.