What's the best place to go shopping in the ocean?

What does this mathematical rebus means ?

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

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

How old is your son? asked a man to his neighbour. My son is five times as old as my daughter and my wife is five times as old as my son. I am twice as old as my wife whereas my grandmother, who is celebrating her eighty-first birthday is as old as all of us put together.

How old is the man's son ?

A man says, "Brothers and sisters, have I none, but that man's father is my father's son." Who is that man?

One absent-minded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he travelled on foot to his friend's place a few miles down the straight desert road. He stayed at his friend's house for the night and when he came back home, he knew how to set his clock. How did he know?

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

What Does this text mean:

important=important

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?