What does this rebus means ?

PROG WORKRESS

A guard is positioned at the one side of the bridge saying ‘A’. His task is to shoot all those who try to leave from ‘A’ to the other side and say ‘B’. He also need to welcome the person who comes from another side ‘B’ to his side ‘A’. The guard comes out of his post every 1 hour and looks down the bridge for any people trying to leave. You are at side ‘A’ and wish to go to another side ‘B’. you also know that it would take 1:45 hr to cross the bridge. How will you cross the bridge?

A Scientist was fifty years old in the year 2000 but he was forty years old in the year 2010. How can this be possible?

PS: It has a logical answer.

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

I am a type of word that is spelt incorrectly or used differently, on purpose for humour. What am I?
Hint 1: You can find me in a joke.
Hint 2: I am a play on words.

On her drawing table, Sayna lit 12 coloured candles. A few seconds later she blew two candles off.

How many candles Sayna have at the end?

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.....)

You have an empty wine bottle with a cork that has been secured at the top in a normal way. There is a metal ring inside the bottle that is suspended by a string.

How can you make the metal ring drop to the bottom if you are not allowed to touch anything - not the bottle, not the cork, not the thread and not the ring?

Find the value of "a" by solving the maths equation in the picture below:

I have 50 feet long of cloth, I need to create 50 handkerchiefs each size of 1 foot. I take one minute to cut a 1-foot handkerchief. So how long will it take to cut 50 handkerchiefs?