What occurs twice in a week, once in a year but never in a day?

Today is John's birthday.
A year ago, John had five candles and he lit all the candles except the one at the last.
Now he is going to light all the candles.

How old is John Today?

(He is not five today.....)

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

What does this rebus mean?

O
N
C
E
TIME

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?

John’s parents have three sons: Snap, Crackle, and what’s the name of the third son?

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?

It is raining today at 11:59 am. What is the probability of sunny weather after 72 hours?

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

Bopanna was working on a murder case when he received a message about the location of the murder weapon.
The message was encrypted as below.

"deb mitciv eht edisni neddih si nopaew redrum ehT"

Tell me the location of the murder weapon.