Can you solve the below tricky visual equation?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

What has one letter and starts with an E?

I have a clock(12-hour format) and both the needles of the clock overlap at 12:00.
After how much time, they will overlap again?

What can go up a chimney down, but can’t go down a chimney up?

There are two candles. Both will only burn exactly for an hour. How will you use these two candles to measure forty-five minutes?

There was once a college that offered a class on probability applied to the real world. The class was relatively easy, but there was a catch. There were no homework assignments or tests, but there was a final exam that would have only one question on it. When everyone received the test paper it was a blank sheet of paper with a solitary question on it: 'What is the risk?'.Most students were able to pass, but only one student received 100% for the class! Even stranger was that he only wrote down one word!
What did he write?

After teaching his class all about Roman numerals (X = 10, IX=9 and so on) the teacher asked his class to draw a single continuous line and turn IX into 6. The teacher's only stipulation was that the pen could not be lifted from the paper until the line was complete.

John was piloting a plane behind a car but was never able to overtake it. Why?

What work can one never finish?