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

I have some blue and red sock in my drawer. I have a total of 4 socks. I pick 2 socks and the chance that I get a pair of red socks is 1/2.

What is the chance of picking a pair of blue socks?

What is red and smells like blue paint?

Only one colour, but not one size,
Stuck at the bottom, yet easily flies.
Present in sun, but not in rain,
Doing no harm, and feeling no pain.
What is it?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.

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

What is in seasons, seconds, centuries and minutes but not in decades, years or days?

Can you solve below mathematical equation?

2^1234 - 2^1233

Replace the question mark with the number below given a simple math problem.

Consider this: Arnold Schwarzenegger has a big one. Michael J. Fox has a small one. Prince doesn’t have one. The Pope has one but never uses it. Bill Clinton has one and uses it all the time. What is it?