If 21x = 79x, what is the value of x?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

I’m orange, I wear a green hat and I sound like a parrot. What am I?

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?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

Spelt forwards I’m what you do every day, spelled backwards I’m something you hate. What am I?

I am white when I am dirty, and black when I am clean. What am I?

Jessica is telling her friends this story and asks them to guess if it’s the truth or a lie: “There was a man sitting in a house at night that had no lights on at all. There was no lamp, no candle, and no other source of light. Yet, he sat in the house and read his book happily.” Her friends say she’s lying, but Jessica corrects them and says she’s telling the truth. Jessica’s story is true—but how?