What is always in front of you but can’t be seen?

The husband and wife were jogging in the morning. To match every two steps of the husband, the wife required three steps. If Both of them start with the here right foot. After how many steps do their left foot be together?

What does this rebus mean?

O
N
C
E
TIME

It is a six-letter word.
The first four letters are me.
The second and last letters are the same.
The fourth second and last letter is payment.

Who is it?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

What's a single-digit number with no value?

You need to arrange three 7 and mathematical symbols to form number 1?

The host of a game show, offers the guest a choice of three doors. Behind one is a expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

What does this mean?

CCCCCCC

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?