People make me, save me, change me, raise me. What am I?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

Can you find the key in the picture below?

What English word has three consecutive double letters?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

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?

Can you solve the tricky chess rebus puzzle below by ciphering the hidden meaning?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

There are 3 apples in the basket and you take away 2. How many apples do you have now?

The person who makes it has no need for it; the person who buys it has no use for it. The person who uses it can neither see nor feel it. What is it?