If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

A person was found dead on a big green land with no trees or buildings around. When the police arrived, they found a piece of rock lying next to him and the man was wearing clothes comprising of red, blue and yellow colours.

Can you tell who the person is and what was the cause of death?

What is the Surname of Barbie Doll?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

Give it food and it will live; give it water and it will die.

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

Can you find the missing piece of the Porsche?

Can you spot what's wrong with the following sentence?

PETER WAS ANGRY AT
HIMSELF BECAUSE HE
ACCIDENTALLY LEFT THE
THE KEYS TO HIS CAR
AT HIS FRIEND'S HOUSE.