Can you convert the number zero(0) into a positive number using just one mathematical operator ?

What is more useful when it is broken?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

Optical Illusion: A cat is hiding in plain sight in the backyard. Only the most observant eyes can spot the cat in 7 seconds. Can you? Test your eye power now!

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

What does this rebus riddle means ?

There are forty elephants and they have forty-fore heads. How can this be possible?

You can hear me, but you can't touch or see me.

What am I?

Outside a massage parlour, there is a board that reads
"I only massage those who do not massage themselves."

Reading the above statement, does the masseur massage himself?

You have two hour glasses one measures 7 minutes and the other measures 4 minutes.
Using these two-hour glasses, you need to measure exactly 9 minutes.

How come?